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Identifying Low-Maintenance Hydrangeas

If you drove or walked the three-mile drive at the Minnesota Landscape Arboretum during late summer or fall in 2013, chances are you stopped for a visit at the Earth-Kind® hydrangea trial. Planted in the fall of 2010, this planting exploded with growth and bloom last year and it was hard to resist stopping for a walk through the beds.

K Zuzek, UMN Extension

Photo 1: Locations of the 5 Earth-Kind Hydrangea trials

The hydrangea planting at the arboretum is one of five Earth-Kind® plantings in the Upper Midwest (Photo 1) that are being used to provide information on the performance of 24 hydrangeas being grown under low input maintenance conditions. The Earth-Kind® program was started in the early 1990's by Dr. Steven George at Texas Agrilife Extension Service to promote environmentally responsible landscape management practices that address diminishing water resources, the overuse and misuse of fertilizers and pesticides, and poor soil health that can diminish plant health. Earth-Kind® landscape practices include minimizing irrigation, providing fertility and improving soil health through the use of compost and organic mulches rather than fertilizers, the reduced use of pesticides, and the identification of genetically strong cultivars and species that will perform well under these low input conditions. The hydrangea trial sites are being used both to identify these strong cultivars and as outdoor classrooms to educate the public on environmentally friendly landscape management.

K Zuzek, UMN Extension

Photo 2: Plot preparation at the MLA

Cultivar trial establishment involves creating 4 blocks (planting beds) at each trial site. Each of the 24 cultivars being trialed is planted once in each of the 4 blocks in a randomized design. This means that 4 plants of each cultivar are planted at each site and their location is different within each of the 4 blocks. Four plants at each of the 5 sites provide us with 20 plants of each cultivar to focus our evaluation efforts on. This replication and randomization gives us statistically strong evaluation data to draw conclusions from. Plot establishment includes eliminating native vegetation (this is the one of the few times an herbicide is used) (Photo 2), incorporating 3" of compost into the native soil, planting, and applying 3" of organic mulch (usually wood chips) (Photo 3). Plants receive consistent irrigation as they establish during year 1.

K Zuzek, UMN Extension

Photo 3: Wood chipping during plot establishment

During years 2-4, irrigation is minimized and watering occurs only if plants wilt during periods of severe drought. Throughout the 4 year study, herbicides are applied only to control invasive weeds such as Canadian thistle if they appear in the plots. The 3" mulch layer minimizes weed establishment and weeds that do appear in the plots are removed by hand weeding. No fertilizers are applied. Organic mulch is reapplied as needed to maintain a 3" depth.

K Zuzek, UMN Extension

Photo 4: MLA plots in year 2 (July 2012)

During years 2-4, evaluation data is collected monthly on the 96 plants at each site. Data is collected on floral and foliar quality, plant size and habit, tolerance to environmental stresses (cold hardiness, drought tolerance, high soil pH, etc.), disease and insect tolerance, and the ability to perform well across a wide variety of soil conditions. Superior hydrangea cultivars that perform well across years and trial sites will be designated as Earth-Kind plants for their region so that gardeners and horticultural professionals know that these cultivars perform well with basic plant care.

K Zuzek, UMN Extension

Photo 5: MLA plots in year 3 (July 2013)

Twenty-four hydrangea cultivars were planted in the trial. Fourteen of the cultivars are panicle hydrangeas (Hydrangea paniculata) and include First Editions® Great Star, First Editions® Tickled Pink®, First Editions® Vanilla Strawberry™, First Editions® White Diamonds®, 'Grandiflora' (also known as PeeGee), 'Limelight', 'Little Lamb', Little Lime™, 'PeeGee Compact', 'Pink Diamond', Pinky Winky™, Quick Fire®, 'Tardiva', and 'Unique'. Seven of the cultivars are smooth hydrangeas (H. arborescens) and include 'Anabelle', 'Bounty', Endless Summer® Bella Anna®, 'Hayes Starburst', Incrediball®, Invincebelle® Spirit and White Dome®. The remaining three cultivars are bigleaf hydrangeas (H. macrophylla) and include Endless Summer® Blushing Bride, Endless Summer® The Original, and Endless Summer® Twist-n-Shout®.

The Benefits of Earth-Kind®
Low input gardening and the identification of plant cultivars that thrive with minimal maintenance benefit gardeners and the environment. The use of genetically strong and well-adapted plants makes it much easier and more enjoyable for gardeners and landscapers to create and maintain beautiful landscapes. There is also a large reduction in labor and the cost of maintenance. Few plants need replacing if adapted and pest-tolerant cultivars are selected for use in a landscape. The use of these tolerant cultivars minimizes the amount of irrigation needed and the use of pesticides. Replenishing organic mulches can be labor intensive but the benefits to gardeners and plants far outweigh the added labor. Mulch provides weed control, reduces the need for irrigation by decreasing evaporation of water from soil, and buffers soil temperature to protect roots during the intense cold of winter and the heat of the growing season. As it decomposes mulch improves soil structure and creates healthier root environments for garden plants: nutrient- and water-holding capacity increase in sandy soils and soil porosity, water infiltration and drainage, oxygen levels, and root penetration improve in heavier clay soils. The health and appearance of plants improves as soil quality improves. Improved soil texture also goes a long way towards making the job of hand weeding a much easier task for gardeners.

As individuals, the impact of our landscape management practices on the environment may be very small but collectively we have an enormous and sometimes a negative impact. As we change our gardening practices, we can reduce or eliminate these negative impacts. Fertilizers and pesticides have the potential to decrease water quality if they move over impervious surfaces such as driveways and sidewalks and into our streams, rivers and lakes through storm sewer systems. As the use of these chemicals is reduced, so is the potential for them to reach the water bodies that we treasure so much in Minnesota. The use of water-wise practices such as drip irrigation and the selection of drought-tolerant plants help to conserve water resources in a time when climate change is creating longer and more frequent periods of drought that put additional demands on these diminishing water resources. The use of organic mulches improves soil quality and reduces the amount of yard waste entering landfills.

The benefits of low input landscape management practices have been documented in Texas where the Earth-Kind® program has been in existence for over 20 years. In gardens or communities where Earth-Kind® landscape management practices are practiced, there have been 50-70% water savings, a 98% reduction in the use of pesticides, and a 20% reduction of yard waste entering landfills. In Addison, TX where the parks & recreation department uses Earth-Kind® management, there was a 50% reduction in labor costs due to the reduced need for irrigation, weeding, fertilizers and pesticides, and replanting. The department saw a 70% reduction in water usage and lost the dubious honor of being the town's largest water consumer.

The effectiveness of the Earth-Kind® plant evaluation effort can also be seen in Texas. To date, 23 roses have been designated as Earth-Kind roses for the southern United States. These plants have high tolerances to pests and perform beautifully under harsh summer temperatures and drought conditions such as those seen in 2011 when Dallas set records for the most 100 degree days, highest daytime and night temperatures, and drought (3.6" of rainfall from March to August instead of the average 17").

Mary Meyer, Extension Horticulturist

Mary Meyer

Figure 1: Ostrich fern background, maidenhair fern foreground

Mary Meyer

Figure 2: Gooseneck loosestrife has almost comical flowers

Mary Meyer

Figure 3: Northern seaoats' flowers are pendulous and easily self-seed

Mary Meyer

Figure 4: From left 'Northwind', Warrior', 'Thundercloud', and Cloud 9' Switchgrass

My backyard is at the bottom of a slope that easily floods when we have a 'rain event' of a few inches. The water can even stand in this area for 12-24 hours - fatal for some plants. To make matters worse, the soil is sandy, so when rain is scarce, the soil is bone dry- again fatal again for some plants. I have three tough perennials that have lived well in this area, all of which are shade tolerant: ostrich fern, Canada anemone and gooseneck loosestrife. All three of these plants have aggressive rhizomes that have helped them to live in this difficult site. I believe all of these plants will grow well in USDA Plant Hardiness Zone 3. However, northern seaoats will only live as an annual, but it will self-sow enough to come back each year.

Ostrich fern (Matteuccia struthiopteris) is a tough native fern (photo 1). Some people may think the ostrich fern is too tough, with its rhizomes and substantial root system. I love the soft feathery fronds and the fact that it will tolerate standing water and survive droughts. In the driest years, the plants are shorter, the rhizomes do not spread, and the plants die back prematurely. In wet years, it begins very aggressively and grows into the adjacent lawn. I transplant it to other shady locations where I want it to grow. The fertile fronds are stiff, much shorter and still standing in the spring when I break them off and push them into the ground as a standing border for the sedge planting that is up the hill under the box elder. This acts as a border signaling my husband where to mow the lawn and not the sedges.

Canada anemone (Anemone canadensis) is another tough native that easily can be too aggressive due to creeping rhizomes. However, the tough conditions of this site keep it in bounds. It is a sea of 1-2 foot tall white flowers in the spring. The foliage is often confused with wild geraniums, but the single white flowers have a cluster of yellow stamens, typical of the buttercup family, and lack the beak-like style of geraniums. Canada anemone foliage makes a thick ground cover that competes well with other weeds, even buckthorn seedlings!

Gooseneck loosestrife (Lysimachia clethroides) is a 2-3 foot tall perennial native to China (photo 2). I am adding it anyway because it has lived in this tough situation as few other plants would. It also has aggressive rhizomes. In dry years the plants are short and do not spread at all, while In wet years it is tall and robust. I step on it to keep it in bounds as I go to the compost pile, or edge it with the lawn mower. The gooseneck flowers are fun to look at and a delight in floral arrangements. It is one plant that blooms regardless of weather conditions.

Other plants (grasses are my favorites!) that I could add in this site are:

Wood oats or Northern seaoats (Chasmanthium latiflium) (photo 3) are native to south central U.S. and marginally hardy in zone 4. This grass self-seeds and although one plant may die, another will likely come up on its own. This is a bunch grass, with no rhizomes. It has the best flowers for dried arrangements and will last for years if picked early before the seeds are fully developed. The pendulous flowers are flat and beautiful in the fall when they turn bronze and yellow. This grass is native in wooded areas along river banks and it prefers wet sites where it can grow to 4 feet. In drier sites it may only be 2 feet tall. A newer form 'River Mist' is yellow and white striped, much shorter e.g. 18 inches, and has only lived as an annual for me.

Prairie cordgrass or slough grass (Spartina pectinata) is a larger, 4-6 foot tall, long-leaved grass for wet sites that will tolerate standing water and lakeshores. Native to prairies and often found in roadside ditches, slough grass has creeping rhizomes ideal for binding lakeshores. This grass is large and coarse, good for larger sites. In areas containing only cattails or reed canarygrass, prairie cordgrass can be added to increase diversity. An ornamental form of prairie cordgrass ('Aureomarginata') has yellow stripes on the foliage and creeping rhizomes. Prairie cordgrass prefers full sun conditions, but can grow in light shade.

Native switchgrass (Panicum virgatum) is in almost every roadside ditch across Minnesota. Many ornamental forms are available; we are trialing 17 of these at the Minnesota Landscape Arboretum Grass Collection (Photo 4). Plan to come in September and pick your favorite. The 2014 Perennial Plant of the Year ('Northwind') was selected by the Perennial Plant Association for its 5 foot tall, stiff upright form and olive green foliage. 'Shenandoah' (4' tall) and 'Ruby Ribbons' (2' tall) both have red foliage and flowers. "Cheyenne Sky' is purple and red and grows to 4 feet tall. Most switchgrass plants will tolerate wet soils quite well. They are taller in wet sites and shorter under dry conditions. Switchgrass is a bunch grass and does not have creeping rhizomes, however, it can self-seed readily. Switchgrass prefers full sun conditions and will only tolerate very light shade.

P1220417.JPGLandscape design is always a popular subject and smart gardeners think "sustainability" when they plan a landscape project. People are eager to try new things in their gardens. Likewise, our season is so short, we have an inherent need at this time of year to get our hands dirty!

Jim Calkins and I are teaching two sessions (May, June) of our landscape design short workshop this spring through the LearningLife program here at the University of Minnesota College of Continuing Education. These are designed for home gardeners who want some good basic fundamentals on sustainable landscape design that they can apply in their own yards and gardens. These are intensive classes and are by no means meant to replace the huge benefits of securing the services and talents of a professional designer. What we have found is that after taking our workshops, people stop making - like choosing an 10x10 ft shrub for a 5x5 ft area or thinking they need to keep trying to grow turfgrass in a narrow shady side strip along their house.

Hope you can join us at one of our upcoming sessions! They are lots of fun and loaded with information. Visit the link below for more information:  U of Minnesota College of Continuing Education LearningLife Program.

P1230029.JPGIn 2013, our Legislature directed the Minnesota Department of Agriculture to develop BMPS - "best management practices" - for protecting insect pollinators - bees, moths, wasps, butterflies, etc. The MDA has published the Pollinator Report: Pollinator Bank, Habitat Protection and Pesticide Special Review. I am still reading it. Thought you all might like to as well.

As noted in the Executive Summary (pg. 4), the objectives of the report are: "(i) provide interpretations of the term 'pollinator bank' and propose feasibility, constraints, and uncertainties of the various interpretations; (ii) delineate past, present, and future efforts by MDA, DNR, UMN, MPCA, BWSR and MnDOT to create and enhance insect (native and commercial) pollinator nesting and foraging habitat, as well as to establish and protect pollinator reserves or refuge areas by using Best Management Practices (BMPs); (iii) discuss efforts and progress on developing BMPs to establish, enhance, protect, and restore pollinator habitat that will ultimately be incorporated into pesticide applicator and inspector training; (iv) outline the process and criteria of a special review of neonicotinoid insecticides, and provide a status update on the process, criteria, and progress of the special review of neonicotinoid pesticides registered by the Commissioner for use in this state currently and in the future."

Feel free to pass it on!

Minnesota's Native Holly

K. Zuzek, UMN Extension

Photo 1: Winterberry, November 11, 2013

Mention holly during the month of December and we all think of cut holly branches adorning homes during Christmas season. But our native holly, called winterberry or Ilex verticillata, is just as ornamental outdoors in our early winter landscapes because of its colorful and abundant fruit (Photo 1).

Winterberry is native throughout the eastern United State (Photo 2) and in Minnesota it is usually found growing in forested wetlands in the eastern half of the state along with larch, willows, and speckled alder. You may also see it growing along lakeshores and ponds or in acidic sandy soils with high water tables.

USDA Natural Resources Conservation Service Plants Database

Photo 2: Native range of Ilex verticillata

Although there are over 400 species of holly (Ilex spp.) worldwide, less than a dozen species are commonly used as landscape plants. Winterberry is one of these species. Approximately 35 cultivars have been selected within the species for fruit color (red, orange, and gold), fruit size and abundance, and compact plant size.

Winterberry cultivars range in size from 4-10 feet in the landscape. Small, inconspicuous flowers are produced from mid-June to early July. Winterberry's dark green foliage provides a beautiful backdrop to the brightly colored fruit that become showy in September. After leaves drop, the fruit will continue to light up a winter garden until birds find and eat it.

Winterberry is an easy plant to grow in light or heavy soils. Because it is native to swampy areas, it does well in wet conditions. It does prefer acidic soils with a pH between 4.5 and 6.5; chlorosis will develop in high pH soils. The other important fact to remember is that winterberry is dioecious, meaning male and female flowers are produced on separate plants. Besides planting a female cultivar that will produce the showy fruit, you must also plant a male plant whose pollen will be produced at the appropriate time to pollinate the flowers on your female cultivar that will later develop into the fruit. Two male cultivars are available at garden centers: the early blooming 'Jim Dandy' and the later blooming 'Southern Gentleman'. Plant labels and garden center staff can help you select the appropriate male cultivar for your fruiting female cultivar.

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Lavender Globe Lily & Curly Garlic Chives (Allium spp.)

Karl Foord

Photo 1: Curly Garlic Chives (Allium spirale)

Autumn Lily - Late Summer Flowers (Lycoris squamigera)

Karl Foord

Photo 2: Autumn Lily Flowers (Lycoris squamigera)

Lavender Glove Lily (Allium tanguticum 'Summer Beauty')

Karl Foord

Photo 3: Cleome or Spider Flower (Cleome hasslerana)

Blackberry Lily (Belamcanda chinensis)

Karl Foord

Photo 4: Blackberry Lily (Belamcanda chinensis)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Flowering Tobacco (Nicotiana sylvestris)

Karl Foord

Photo 1: Flowering Tobacco (Nicotiana sylvestris)

Karl Foord

Photo 2: Flowering Tobacco (Nicotiana sylvestris)

Cleome or Spider Flower (Cleome hasslerana)

Karl Foord

Photo 3: Cleome or Spider Flower (Cleome hasslerana)

Pot Marigold (Calendula officinalis)

Karl Foord

Photo 4: Pot Marigold (Calendula officinalis)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Joe-Pye Weed (Eupatorium purpureum 'Gateway')

Karl Foord

Photo 1: Joe Pye Weed (Eupatorium purpureum 'Gateway')

Hardy Hibiscus, Rose Mallow (Hibiscus moscheutos 'Blue River II')

Karl Foord

Photo 2: Hardy Hibiscus Rose Mallow (Hibiscus moscheutos 'Blue River II)

Balloon Flower (Platycodon grandiflorus)

Karl Foord

Photo 3: Balloon Flower (Platycodon grandiflorus)

Lesser Calamint (Calamintha nepeta)

Karl Foord

Photo 4: Lesser Calamint with Sweat Bee (Calamintha nepeta)

Karl Foord

Photo 5: Lesser Calamint with Honeybees (Calamintha nepeta)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Prairie Cordgrass, Sloughgrass (Spartina pectinata)

Karl Foord

Photo 1: Prairie Cordgrass, Sloughgrass (Spartina pectinata)

Karl Foerster Feather Reed Grass (Calamagrostis x acutiflora 'Karl Foerster')

Karl Foord

Photo 2: Karl Foerster Feather Reed Grass (Calamagrostis x acutiflora 'Karl Foerster')

Prairie Dropseed (Sporobolus heterolepis)

Karl Foord

Photo 3: Prairie Dropseed (Sporobolus heterolepis)

Dwarf Forms of Prairie Dropseed (Sporobolus heterolepis 'Tara' and Morning Mist')

Karl Foord

Photo 4: Dwarf Prairie Bluestem: 'Tara' left, 'Morning Mist' right (Sporobolus heterolepis)

Prairie Blues and Carousel Little Bluestem (Schizachyrium scoparium)

Karl Foord

Photo 5: Prairie Blues Little Bluestem ( Schizachyrium scoparium 'Prairie Blues')

Karl Foord

Photo 6: Carousel Little Bluestem (Schizachyrium scoparium 'Carousel')

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Bottlebrush Grass (Elymus hystrix)

Karl Foord

Photo 1: Bottlebrush Grass (Elymus hystrix)

River Oats Wood Oats (Chasmanthium latifolium)

Karl Foord

Photo 2: River Oats, Wood Oats (Chasmanthium latifolium)

Elijah Blue Fescue Grass (Festuca glauca 'Elijah Blue')

Karl Foord

Photo 3: Elijah Blue Fescue (Festuca glauca 'Elijah Blue')

Silver Spike Grass (Achnatherum calamagrostis)

Karl Foord

Photo 4: Silver Spike Grass (Achnatherum calamagrostis)

Tufted Hair Grass (Deschampsia cespitosa)

Karl Foord

Photo 5: Tufted Hair Grass (Deschampsia cespitosa)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Fireworks Fountain Grass (Pennisetum setaceum 'Fireworks')

Karl Foord

Photo 1: Fireworks Fountain Grass (Pennisetum setaceum 'Fireworks')

Blue Grama Grass (Bouteloua gracilis)

Karl Foord

Photo 2: Blue Grama Grass - early flowering (Bouteloua gracilis)

Karl Foord

Photo 3: Blue Grama Grass - mature seed heads (Bouteloua gracilis)

Blue Lyme Grass (Elymus arenarius)

Karl Foord

Photo 4: Blue Lyme Grass (Elymus arenarius)

Heat Damage to Blue Lyme Grass (Elymus arenarius)

Karl Foord

Photo 5: Heat damage to Blue Lyme Grass (Elymus arenarius)

Flowering Plant Video Library - Sedges

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Creeping Broadleaf Sedge (Carex siderosticha 'Variegata')

Karl Foord

Photo 1: Creeping Broadleaf Sedge (Carex siderosticha 'Variegata')

Variegated Muskingum Sedge (Carex muskingumensis 'Oehme')

Karl Foord

Photo 2: Variegated Muskingum Sedge (Carex muskingumensis 'Oehme')

Bunny Blue and Silver Sceptre Sedges

Karl Foord

Photo 3: Bunny Blue Spreading Sedge (Carex laxiculmis 'Bunny Blue')

Karl Foord

Photo 4: Silver Sceptre Sedge (Carex morrowii 'Silver Sceptre')

Ice Dance Variegated Sedge (Carex morrowii 'Ice Dance')

Karl Foord

Photo 5: Ice Dance Variegated Sedge (Carex morrowii 'Ice Dance')

Palm Sedge (Carex muskingumensis)

Karl Foord

Photo 6: Native Palm Sedge (Carex muskingumensis)

Rhizomatous vs. Bunching Sedges

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Ruby Ribbons Switch Grass (Panicum virgatum 'Ruby Ribbons')

Karl Foord

Photo 1: Ruby Ribbons Switch Grass (Panicum virgatum 'Ruby Ribbons')

Cloud Nine Switch Grass (Panicum virgatum 'Cloud Nine')

Karl Foord

Photo 2: Cloud Nine Switch Grass (Panicum virgatum 'Cloud Nine')

Panicum Frosted Explosion (Panicum elegans 'Frosted Explosion')

Karl Foord

Photo 3: Panicum Frosted Explosion (Panicum elegans 'Frosted Explosion')

Huron Solstice and North Wind Switch Grass

Karl Foord

Photo 4: North Wind Switch Grass (Panicum virgatum 'North Wind')

Karl Foord

Photo 5: Huron Solstice Switch Grass (Panicum virgatum 'Huron Solstice')

Flowering Plant Video Library - Miscanthus

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Little Fountain Miscanthus (Miscanthus sinensis 'Kleine Fontaine (Little Fountain)'

Karl Foord

Photo 1: Little Fountain Miscanthus (Miscanthus sinensis 'Klein Fontaine (Little Fountain)'

Zebra-banded Miscanthus

Karl Foord

Photo 2: Zebra-banded Miscanthus (Miscanthus sinensis 'Zebrinus')

Giant Miscanthus (Miscanthus x giganteus)

Karl Foord

Photo 3: Giant Miscanthus (Miscanthus x giganteus)

Cautions about the Invasive Character of Miscanthus

Karl Foord

Photo 4: Invasive Miscanthus (Miscanthus sinensis 'Malepartus')

Distinguishing Types of Zebra Banded Miscanthus

Karl Foord

Photo 5: Zebra Banded Miscanthus (Miscanthus sinensis 'Strictus')

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Purple Prairie Clover (Dalea purpurea)

Karl Foord

Photo 1: Purple Prairie Clover (Dalea purpurea)

False Indigo (Baptisia australis)

Karl Foord

Photo 2: False Indigo (Baptisia australis)

Prairie Dock (Silphium terebinthinaceum)

Karl Foord

Photo 3: Prairie Dock (Silphium terebinthinaceum)

Cup Plant (Silphium perfoliatum)

Karl Foord

Photo 4: Cup Plant (Silphium perfoliatum)

Harebell Campanula (Campanula rotundifolia)

Karl Foord

Photo 5: Harebell Campanula (Campanula rotundifolia)

Native Prairie Lily (Lilium philadelphicum)

Karl Foord

Photo 6: Native Prairie Lily (Lilium philadelphicum)

Golden Alexanders (Zizia aurea)

Karl Foord

Photo 7: Golden Alexanders (Zizia aurea)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Great White Trillium, Trillium grandiflorum

Karl Foord

Photo 1: Great White Trillium (Trillium grandiflorum)

False Solomon's Seal (Maianthemum racemosum, syn. Smilacina racemosa)

Karl Foord

Photo 2: False Solomon's Seal (Maianthemum racemosum)

Lungwort, (Pulmonaria officinalis)

Karl Foord

Photo 3: Lungwort (Pulmonaria officinalis

Heucherella 'Stoplight' (Hybrid of Heuchera and Tiarella)

Karl Foord

Photo 4: Heucherella 'Stoplight'

Foam Flower, Tiarella 'Sugar and Spice' and Lungwort, Pulmonaria 'Trevi Fountain'

Karl Foord

Photo 5: Foam Flower (Tiarella 'Sugar and Spice')

Jacob's Ladder, Polemonium reptans 'Stairway to Heaven'

Karl Foord

Photo 6: Jacob's Ladder (Polemonium reptans 'Stairway to Heaven')

Lenten Rose, Helleborus orientalis

Native Grasses for Wildlife

Mary Meyer, Extension Horticulturist and Professor

Grasses, especially native grasses, can attract a wide range of wildlife and insects. While you might first think of the cover grasses provide in summer and winter, they also supply food for many grassland birds and are critical for butterfly larva food. Planting a prairie gives you the best environment for wildlife habitat; however, you can still make an impact with grouping 2-4 kinds of grass and using 3-5 plants of each kind. You could even try a stylized prairie by grouping the grasses in drifts similar to a traditional border. Diversity in a garden not only looks good, but can attract a wider variety of insects and birds. Leaving the grasses standing in winter can provide cover and winter shelter to wildlife. We rarely think of grasses being attractive, let alone critical for butterflies, but many species of skippers, satyrs, pearly eyes, wood nymphs, and browns, REQUIRE grasses and sedges as larval food, so these plants attract a number of butterflies as sites to lay their eggs.

Mary Meyer

Photo 1: A skipper butterfly rests on feather reedgrass. Skippers are a large group of butterflies whose larvae feed on grasses.

Grasslands, which not surprisingly, are predominately grasses, have lost 1,000s of acres to development and agriculture, resulting in drastic declines in grassland birds. Of the 37 species of grassland birds that appear to be reasonably well monitored by the North American Breeding Bird Survey, 32 are demonstrating some form of decline, while only 5 are experiencing some form of increase (Sauer, 2005). Habitat loss is the main reason cited for decline in these grassland species. Adding native grasses in your garden can increase the diversity of your garden and provide a home for native butterflies and birds.

Inviting wildlife into your garden is great especially if it's birds, butterflies, honey bees and other pollinators. What about mice, ticks, snakes and mosquitoes? Yes, this 'less desirable' wildlife lives in grasslands and is all part of nature! Making sure your home is properly sealed from openings for wildlife, wearing protective clothing when walking in tall grass, eliminating standing water for breeding mosquitoes, and mowing paths through areas you want to keep natural are precautions and means for living with the less favorite forms of wildlife.

Click the link below to see table 1 which lists common native grasses and the range of wildlife these plants can attract.

Grasses for Wildlif1.pdf

Species Fact Sheets:
BirdLife International. 2004. Grassland birds are declining in North America. Presented as part of the BirdLife State of the world's birds website. Available from:
Sauer, J. R., J. E. Hines & J. Fallon, 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2004. Version 2005.2. USGS Patuxent Wildlife Research Centre, Laurel, MD

An Imprelis Update

Kathy Zuzek, UMN Extension Educator, Horticulture

The History of Imprelis
In October of 2010, a new broadleaf weed killer by the name of Imprelis became available to turf professionals. Key to DuPont's release of this herbicide was its effectiveness at very low concentrations, its low toxicity to humans and other mammals, and its effectiveness on difficult-to-control turf weeds such as creeping Charlie, wild violets, clover and Canada thistle.

During the spring of 2011, damage to ornamental plants in landscapes where Imprelis had been applied began to appear in the eastern half of the United States including Minnesota. Damage to new growth of plants became visible within a matter of weeks after an Imprelis application and included twisting and/or browning of shoot tips, leaves, and needles (Photo 1).

K. Zuzek

Photo 1: Brown, twisted, & drooping shoot tips from Imprelis applications

As the summer progressed, impacted shoots and their associated leaves, needles, and buds often died on the most susceptible species. In some cases, entire trees or shrubs died. Broadleaf and conifer species of ornamental plants were impacted but conifer species were impacted much more severely. The most seriously impacted species from states east of Minnesota were Norway spruce (Picea abies) and eastern white pine (Pinus strobus) trees. The most seriously impacted species in Minnesota were white spruce (Picea glauca) and eastern white pine, but noticeable damage to Colorado blue spruce (Picea pungens), Norway spruce, Austrian pine (Pinus nigra), red pine (Pinus resinosa), and arborvitae (Thjuja occidentalis) were also common. A wide range of damage was seen among all of these species. Some plants showed little injury throughout the 2011 growing season, others died quickly, and the symptoms on others became more severe as the growing season progressed. The number of plants damaged, the level of damage, and plant mortality was highest among white spruce and eastern white pine in Minnesota.

In August of 2011, sales of Imprelis were stopped but damage to trees and shrubs in landscapes continues to be an issue. DuPont initiated a claims resolution process to compensate customers with damaged or killed plants. The deadline for claims submission was February 1, 2012 and DuPont is now processing claims submissions. Lawsuits have also been filed against DuPont.

How Imprelis Works
Aminocyclopyrachlor is the active ingredient in Imprelis and is classified as a synthetic auxin or growth regulator type of herbicide. Imprelis and other growth regulator herbicides are absorbed by roots and leaves and then move via the xylem & phloem to two of the meristematic regions responsible for new plant growth: shoot tips and root tips. In susceptible plants, growth regulator herbicides produce characteristic twisting and curling of the shoot tips and their foliage and plant mortality often follows. Herbicides are meant to kill and eliminate targeted plants such as weeds. When they impact non-targeted plants such as conifers in the case of Imprelis, problems arise.

Imprelis does not bind well to soil particles and is a very water-soluble compound. It is also a very stable compound in soil. Because it is active over a long period of time in soils and because its low adsorption and high solubility allow it to move downward in soil once applied to turf, it appears that Imprelis was able to reach the root systems of ornamental plants. Absorption of the herbicide occurred through the roots of these plants, followed by movement through the plant to new growth areas, and injury occurred. It is still not known why particular spruce and pine species are so susceptible to Imprelis.

K. Zuzek

Photo 2: Branch with active bud-break


K. Zuzek

Photo 5: Branch with no bud-break

Will Trees Damaged by Imprelis Recover? The answer to this question depends on the severity of damage. Trees that showed minimal damage (such as a small amount of injury at shoot tips in the upper branches of a tree) during the spring of 2011 and had little additional decline during the growing season will probably survive.These trees have active bud-break and are putting on new growth throughout most of their crowns this spring (Photo 2). Most broadleaf trees and shrubs and some of the conifer species that were impacted by Imprelis are in this group. Retaining these trees and shrubs in the landscape will depend on how badly damage impacts their appearance. Care of these plants during the recovery period should include irrigating the plants during dry periods to minimize moisture stress, avoiding over-watering that can cause additional stress, and avoiding fertilization for a minimum of one growing season to avoid excess growth that can compound herbicide injury.

Trees that showed damage last spring (Photo 3), further decline (dieback of shoots, dead needles and buds, yellowing of the tree canopy) during the 2011 growing season and/or the winter of 2011-2012 (Photo 4), and limited or no bud-break throughout the tree crown this spring (Photo 5) will probably continue to decline and then die. Even if these trees do not die, they will be of little or no aesthetic value in the landscape. In Minnesota, the majority of trees in this group are white spruce and eastern white pine.

K. Zuzek

Photo 3: Initial symptoms on white spruce in July, 2011

K. Zuzek

Photo 4: Symptoms on the same white spruce in April, 2012

DuPont's Compensation Plan If you are a property owner with Imprelis-damaged plant materials and you and your lawn care professional are part of the claims resolution process that DuPont enacted, you can access information on the claims process here. Compensation will cover removal and disposal of impacted trees, replacement costs or direct payment for removed trees, care of replacement trees , two-year warranties for all replacement trees and for any other trees impacted by Imprelis over the next two years, maintenance of impacted trees as they recover, and additional compensation for inconveniences associated with Imprelis.

Removal and Disposal of Plant Materials and Soil containing Imprelis
Listed below are some of Dupont's recommendations for the disposal of plant materials and soils containing Imprelis. These recommendations are for individuals who had Imprellis damage to plant materials but are not part of the claims process against DuPont. You can access the full list of recommendations here .

    Disposal Recommendations
  • No tree debris should be left on site.
  • DuPont recommends disposal of tree and excavated soil materials in solid waste landfills that will accept such waste.
  • The Imprelis label prohibits the use of grass clippings for mulch or compost.
  • Under no circumstances should tree material be used for mulch or compost or disposed of in facilities that would turn it into compost or mulch (e.g., recycling).
  • Trees that are cut down may be used for lumber, firewood, or to fuel various wood burning processes if such usage is otherwise consistent with state, regional and local regulations. Open burning is also an alternative if approved under local regulations.
  • If not landfilled, excavated soil should be disposed of in locations where it will not impact any other plantings through direct application or runoff. With the property owner's consent, excavated soil may be used on site as long as it is applied well away from desirable plant root.
Recommendation for planting replacement plants:
  • To address potential effects of Imprelis remaining in the soil, activated charcoal (that serves to deactivate any residual herbicide) should be applied to the backfill soil in accordance with manufacturer's instructions:

  • For liquid applications, apply at a rate of 1 pound of activated charcoal in each gallon of water uniformly to sides and bottom of hole dug for tree planting as well as to the complete root ball of the tree to be planted. Also, spray the burlap covered root ball if burlap is left in place. Thoroughly coat to the point of run-off the surfaces of the hole and the root ball.

    For dry applications, during tree planting, apply activated charcoal at a rate of 7 to 14 lbs/1000 cubic feet of soil and thoroughly mix with the clean soil. Use this soil as the new backfill soil when planting the tree.

  • Excavated soil should not be used as backfill. New soil, of a similar nature as the existing soil, should be used to backfill around the root ball. No fertilizer should be added to the backfilling mixture.

  • The replacement plant should be watered according to nursery recommendations.

  • The property owner should ensure adherence to best management practices consistent with the geographic area in which it is performing this work, taking into account any unique environmental and climate conditions, and any state, regional or local ordinances. Information on selecting, planting, and care of trees in Minnesota can be found here.

Based on the degradation rate of Imprelis in soils and on recommended planting times for Minnesota, a good additional recommendation would be to not plant susceptible species into Imprelis-impacted landscapes until September of 2012.

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Trout Lily (Erythronium americanum)

Karl Foord

Photo 1: Trout Lily (Erythronium americanum)

Virginia Bluebells (Mertensia virginica)

Karl Foord

Photo 2: Virginia Bluebells (Mertensia virginica) flower

False Rue Anemone (Enemion biternatum)

Karl Foord

Photo 3: False Rue Anemone (Enemion biternatum)

Minnesota Dwarf Trout Lily (Erythronium propullans)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

American Pasqueflower (Anemone patens) and Prairie Smoke (Geum triflorum)

Karl Foord

Photo 1: American Pasqueflower (Anemone patens)

Karl Foord

Photo 2: Prairie Smoke (Geum triflorum)

Bloodroot (Sanguinaria canadensis)

Karl Foord

Photo 3: Bloodroot (Sanguinaria canadensis

Double Bloodroot (Sanguinaria canadensis 'Multiplex')

Karl Foord

Photo 4: Double Bloodroot (Sanguinaria canadensis 'Multiplex'

Marsh Marigold (Caltha palustris)

Karl Foord

Photo 5: Marsh Marigold (Caltha palustris)

Wild Ginger (Asarum canadense)

Karl Foord

Photo 6: Wild Ginger (Asarum canadense)

Plant Video Library - Bulbs I

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Glory of the Snow (Chionodoxa luciliae)

Karl Foord

Photo 1: Glory of the Snow ( Chionodoxa luciliae) flower close-up

Checkered Lily (Fritillaria meleagris)

Karl Foord

Photo 2: Checkered Lily (Fritillaria meleagris) flower

Species Tulips (Tulipa tarda)

Karl Foord

Photo 3: Species Tulips (Tulipa tarda)

Garden Hyacinth (Hyacinthus orientalis)

Karl Foord

Photo 4: Garden Hyacinth (Hyacinthus orientalis)

Autumn Lily (Lycoris squamigera)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Triumph Tulip (Tulipa 'Gavota)

Karl Foord

Photo 1: Triumph Tulip (Tulipa 'Gavota')

Grape Hyacinth (Muscari armeniacum)

Karl Foord

Photo 2: Grape Hyacinth (Muscari armeniacum)

Daffodils (Narcissus)

Karl Foord

Photo 3: Daffodils (Narcissus"Saint Keverne')

Dwarf Bearded Iris (Iris 'Joyce McBride)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Barrenwort (Epimedium x rubrum)

Periwinkle (Vinca minor 'Dart's Blue')

Pennsylvania Sedge (Carex pensylvanica)

Karl Foord - Extension Educator, Horticulture

Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture

Sungold and Moongold Apricots (Prunus armeniaca mandshurica 'Sungold' & 'Moongold'

Karl Foord

Photo 1: Apricot Flower (Prunus armeniaca)

Karl Foord

Photo 2: Young Apricot Fruit (Prunus armeniaca)

Regent Serviceberry (Amelanchier alnifolia 'Regent'

Karl Foord

Photo 3: Regent Serviceberry (Amelanchier alnifolia 'Regent'

Northern Strain Redbud (Cersis canadensis 'Northern Strain')


Karl Foord

Photo 4: Northern Strain Redbud (Cersis canadensis 'Northern Strain')

Emerald Triumph Viburnum (Viburnum 'Emerald Triumph')

Flowering Plant Video Library

Karl Foord - Extension Educator, Horticulture

This is the beginning of a flowering plant video library. The goal of this library is to give a short, guided, visual, one to two minute introduction to flowering plants that thrive under Minnesota conditions. You will be able to see the plant in a natural or landscape setting and see how it might fit into your landscape.

We will begin with three early flowering bulbs Snowdrops, Striped Squill, and Siberian Squill. The library will continue to grow and we hope that you will find video to be an enjoyable way to learn about and experience flowering plants.

Striped squill (Puschkinia scilloides var. libanotica)

Snowdrops (Galanthus nivalis)

Siberian Squill (Scilla siberica)

A Look at the New USDA Hardiness Zone Map

A hardiness zone map (HZM) provides information that gardeners and professional horticulturalists use in determining which herbaceous and woody perennial plants will survive cold temperature in a particular geographic area. Last week the United States Department of Agriculture released a new hardiness zone map to replace the older 1990 version.

As with past maps, the new map:
  • is a visual representation of average annual minimum temperatures across the United States. Data points used to create the map were the lowest daily minimum temperatures recorded at thousands of temperature data stations during each of the years sampled.
  • divides the U.S. into multiple hardiness zones with 10o F differences in average annual minimum temperatures. Zone 1 is the coldest zone (-50o F to -60o F).
  • divides each hardiness zone into "a" & "b" with "a" being the colder half of any zone and "b" the warmer half.

There are changes in the new map and the process that was used to develop it:


    Photo 1: 1990 USDA Hardiness Zone Map

  • The 1990 HZM was based on data from a 12-year period (1976-1990) while the new HZM is based on data from a 30-year period (1976-2005).
  • The data used to create the new map was more complete, and a complex algorithm was used to interpolate between recording stations. Temperature data from more than 8000 temperature data stations belonging to the National Weather Service, the USDA Natural Resources Conservation Service, the USDA Forest Service, the Bureau of Reclamation, and the Bureau of Land Management was used. Average minimum temperatures were then calculated for ½ mile square computer grids for the entire country to create the new hardiness zone map. This was followed by a review process that included climatologists, agricultural meteorologists, and horticultural experts who checked for errors, looked for the source of errors, and corrected errors.


    Photo 2: 2012 USDA Hardiness Zone Map

  • The new map is Geographic Information System-based. This means that the map is more accurate, is interactive (by zip code) to improve user experiences, and has higher resolution that can show smaller areas of zone delineations than before. While the 1990 map was a static image and was not designed for web use, the new map allows users to zoom in to a local area to see the higher temperatures of cities that are heat sinks, the lower temperatures on mountain tops, and the buffering effects of large bodies of water on temperature.

What does the new hardiness zone map show?
In general, the new map shows what we have all been experiencing in recent history: warmer low temperatures during winter. A shift of ½ of a zone was common for much of the country. Closer to home, here is what happened to Minnesota's hardiness zone map:


    Photo 3: 1990 USDA MN Hardiness Zone Map


    Photo 4: 2012 MN Hardiness Zone Map

  • There was a ½ zone shift for much of the state because Minnesota, like the rest of the U.S., has been experiencing warmer annual minimum temperatures during the time period used to create the new HZM.
  • Zone 5a (with average minimum temperatures of -15o to -20o) crept up into the south central portion and the far southeastern corner of Minnesota.
  • Much of the southern ½ of Minnesota that was formerly divided into zones 4a & 4b is now zone 4b (with average minimum temperatures of -20o to -25o).
  • The four pockets of Zone 2b (with average minimum temperatures of -40oto -45o) disappeared from northern Minnesota.
  • The amount of Minnesota that is zone 3a (with average minimum temperatures of -35o to -40o) shrank significantly due to an increasing area of zone 3b (with average minimum temperatures of -30o to -35o).
  • Parts of the far northern shore of Lake Superior that were formerly zones 4b and 4a are now designated as 4a and 3b, meaning they are colder.

What kind of impact should the new hardiness map have on Minnesota gardeners?

  • We can all rest easy knowing that the warmer minimum annual temperatures we have been enjoying over the past years really did happen!
  • Remember that a HZM is created based on average annual minimum temperatures and should only be used as a general guide. By the very definition of average, we know that temperatures lower than the average minimum temperature of the zone you live in will occur. Pick your plants accordingly. Maybe we can broaden the palette of plants we choose to grow in Minnesota a bit, but be cautious and wise in your weighing of risk vs. gain as you trial new plants. Losing an herbaceous perennial or quickly-maturing shrub to winter injury may be of little concern in terms of the time it takes to establish a replacement plant. Losing a slow-growing shrub or a tree that takes decades to grow to mature size creates more pain.
  • Hardiness zone maps are of no help in predicting plant damage or mortality during acclimation and deacclimation. Remember that hardiness is not just about the lowest temperature a plant must survive during a winter. Every year, starting in late summer, perennial plants goes through a multi-month process called acclimation that prepares them for winter survival. In spring dormant plants go through a reverse process called deacclimation that restores their ability to actively grow during the growing season. Plants can be winter-injured or killed by abnormally low temperatures during the months of acclimation and deacclimation too. This is especially true of marginally hardy plants from warmer parts of the country or world that we may try to grow in Minnesota.
  • Hardiness zone maps provide gardeners with one category of plant performance information: winter survival. Good plant performance is not just about winter survival. If the new HZM persuades you to plant cultivars and species new to you, remember that there are other selection categories to consider as you match a plant to your planting site: soil texture, soil moisture, soil pH, light exposure, precipitation, etc.

What's New or What's Good

Kathy Zuzek, UMN Extension Educator, Horticulture

An enormous interest for most gardeners during our long winter is the search for new cultivars that can be added to next year's garden. But is new always good? The answer to that question depends on whether new cultivars have been shown to perform well in Minnesota gardens before their introduction into garden centers. Horticultural professionals should provide customers with the best performing plant selections for Minnesota's difficult climate. But the current trend in horticulture is to move new plants onto the market in the shortest possible time frame, creating a rapid process of both cultivar introduction and elimination in the market.

This creates several problems for gardeners interested in sustainable gardening and in planting cultivars known to have long-term landscape value. New cultivars are now introduced to Minnesota gardeners from breeding and evaluation programs around the world. When new cultivars are rushed to the market, there is often no time for the evaluation of the plant's performance in Upper Midwest gardens prior to introduction. Purchasing and planting new un-trialed cultivars among annuals or herbaceous perennials may be an acceptable risk for gardeners to take. These plants are relatively inexpensive and establish and grow to maturity quickly. It is much riskier in terms of money, labor, and time invested if gardeners purchase and grow un-trialed shrubs and especially trees that take decades to reach maturity.

If newly introduced cultivars are displaced quickly by even newer cultivars, there is also little time to evaluate their long-term potential in the landscape between their introduction and their elimination from nursery catalogs. This sets up a situation where newer cultivars prove to be a good performer in our Minnesota gardens but by the time this fact is recognized, the plant has already been removed from nursery catalogs.

The emphasis on new cultivars may also result in the elimination from the nursery trade of much older cultivars as they are removed to make room for new cultivars in a nursery's production schedule. The introduction of new cultivars that have been shown to be improvements over older cultivars is an exciting event for gardeners, especially for northern gardeners who have a smaller pool of plants to choose from than southern gardeners. But what if older cultivars that have proven their long-term landscape value over decades of time are replaced with un-trialed cultivars that fall short of the mark?

As wise gardeners, we can help solve these problems by asking "What's good?" rather than "What's new?" Finding information on plant performance in Minnesota or the Upper Midwest can be a tough go though. Here are some suggestions:

Take advantage of the information available from plant evaluation programs. Plant evaluation programs for the Upper Midwest are few and far between but here are a few examples:

  • The Chicago Botanic Garden has been home to the Plant Evaluation Program for 28 years.

    Kathy Zuzek

    Photo 1: Plant Evaluation Notes

    The goal of this program is to determine, through scientific evaluation, which annuals, perennials, vines, shrubs, and trees are superior for gardens in the Upper Midwest. Information on the program and the 35 Plant Evaluation Notes published to date can be found here.

  • The All-America Selections program was founded in 1932 and is a national program that annually evaluates and identifies new garden seed varieties with superior garden performance based on impartial trialing at 47 sites throughout North America. The horticultural garden at the West Central Research and Outreach Center in Morris, Minnesota is home to one of these test sites. More information on this evaluation program can be found here.

  • Look for information on cultivar introductions and evaluations from universities and their affiliated Extension services in the Upper Midwest.
  • The University of Minnesota's Department of Horticulture is home to research programs that develop cultivars of turf grasses, herbaceous perennials, ornamental shrubs and trees, and fruit crops. Cultivars developed through the efforts of these research programs are highlighted here in a publication titled Minnesota Hardy. Information on garden plant selection can also be found on the University of Minnesota Extension Garden web page.

  • North Dakota State University's Department of Plant Sciences has selected 42 ornamental shrub and tree cultivars that perform well in North Dakota's Zone 3, low moisture climate. Many of these cultivars perform well in Minnesota too. Information on these cultivars can be found here.
  • Ask for information from your knowledgeable gardening friends, garden center staff, and any landscape design and maintenance professionals whose objective knowledge you value. Cultivar information provided by knowledgeable friends and objective horticultural professionals may be anecdotal, but this is often the best information we have given the dwindling support for formal plant evaluation programs. These are the people who will know plants that have stood the test of time in Minnesota landscapes.

    Visit the Minnesota Landscape Arboretum grounds and website regularly to view plants that are hardy enough to grow in Zone 4 and sometimes Zone 3. The arboretum is home to thousands of ornamental cultivars of annuals, herbaceous perennials, ornamental shrubs and trees, and vegetable and fruit cultivars.

  • Information on the locations of cultivars of particular interest to you is readily available from arboretum staff.

  • Use the arboretum as an outdoor classroom. A few visits during the year can provide you with practical information on cultivars of interest to you. Observing plants during their seasons of interest whether it is during bloom display, fruit display, fall color, or in winter, can be most helpful. Visits in late summer and early fall to view overall plant appearance give good visual information on how well a plant has tolerated disease and insect pests throughout the growing season.

  • Check out the plant labels as you observe perennial herbaceous or woody cultivars you are interested in. Labels of plants in permanent plantings will have an 8-digit number on them. The first four numbers will give you a close approximation of the year the cultivar was planted, plant age, and how long the plant has been growing at the arboretum. For example a label reading "19880247" indicates a plant that was planted in 1988 or shortly afterwards.

  • Kathy Zuzek

    Photo 2: Plant Info link on the arboretum website

  • Check out the Plant Info tab on the arboretum website.

    A visit to this webpage can provide information on wholesale and retail nurseries that provide mail order service and carry your plant of interest. The webpage also has links to and lists of other websites, books, and magazines carrying information about and photos of your plant of interest.

  • Karl Foord, UMN Extension Educator

    Photo 1: Canada thistle rosette in lawn.

    Whenever I weed my gardens I always manage to find a number of Canada thistle plants, Cirsium arvense (L.) Scop. These are not the rosette seedlings that I see in my lawn which are fairly easily dealt with (photo 1). These are aerial shoots coming from established roots (photo 2). A mixed planting garden bed presents its own set of problems in dealing with this weed. Why is Canada thistle so persistent?

    Missouri State University

    Photo 2: Canada thistle underground root structure and aerial shoots.

    Canada thistle is persistent for three reasons. Seed production, deep roots giving rise to stems, and root pieces that can regenerate plants.

    Seed production per plant averages 1,500 seeds per plant but vigorous plants have been known to produce more than 5,000 seeds with viabilities greater than 20 years. So it will take persistence to reduce the seed load in the soil. Lesson 1: never let thistle go to seed. This will not remedy seeds coming in from an adjoining property, and seeds are reported to be able to travel a half mile in the wind.

    Purdue University

    Photo 3: Two years underground growth of Canada thistle from original one foot of root.

    Canada thistle can reliably regenerate from half-inch long cut root pieces. Lesson 2: attempts to dig out the plant or chopping it up will likely not be successful and may only serve to propagate it.

    Canada thistle is a perennial with a complex system of deep-seated roots that spread horizontally and give rise to aerial shoots (photo 2). The seedlings grow slowly at first producing a fibrous taproot which thickens and develops lateral roots in 7-9 weeks. Aerial shoots usually develop from buds on the branches of the horizontal system. The root system goes deep (6 - 10 ft.) and wide (> 10 ft. per year) with some 60% of roots existing at depths greater than 2 ft (photos 3 and 4).

    Purdue University.

    Photo 4: Extensive underground root systems of Canada thistle.

    To eliminate Canada thistle one needs to prevent regrowth from the potentially extensive underground root system. The non-chemical approach involves strategies that persist until the starch reserves in the roots are exhausted. The chemical approach involves application of herbicides at the correct dosage avoiding damage to nearby plants.

    Simply removing the aerial shoots can eventually exhaust the root reserves. One study showed that mowing the plants would eliminate the top growth similar to pulling the aerial shoots, but will not deplete the starch reserves unless it is repeated at 7-28 day intervals for up to 4 years. It is more likely that the thistle would win given this strategy.

    If the plant can be isolated, it can be smothered with an impenetrable barrier like plastic or a landscape weed cloth. This would require clearing out the bed and dedicated time to starving the root system. The key problem here is isolating a plant with a creeping underground root system that could send up shoots in adjoining areas which would replenish the root system.

    Photo 5: Canada thistle in sedum bed. A situation where a bedding plant could be isolated from spray on a Canada thistle.

    If the chemical route is chosen, a non-selective herbicide like glyphosate (Roundup®), which has little or no soil residual, would be the chemical of choice. In some situations sensitive plants can be separated from the thistle and protected from spray with a physical barrier like plastic (photo 5). The plastic may be removed as soon as the spray dries.

    Photo 6: Canada thistle in cotoneaster bed.

    In other cases protecting sensitive plants is not possible such as a thistle nestled in a cotoneaster bed (photo 6). In this case one can apply material with a paint brush or spot spray taking care not to get spray material on the sensitive plant, and if you do wash it off immediately.

    The goal is to kill the root system by getting as much chemical throughout the plant as possible. Use the lower of label recommendations as higher rates will kill the leaves and not get to the roots making the treatment ineffective. Make sure that the plants are not drought-stressed and that there is plenty of moisture. If the plants are stressed the chemical will not be effectively translocated throughout the root system. Be sure to read and follow all label directions carefully. It is highly likely that multiple applications may be needed to eradicate this weed.

    Given the look of the below ground root systems it looks like the most we can hope for with Canada thistle is not elimination but rather a certain level of control.

    "Canada Thistle." Midwest Weeds, Missouri State.

    "Control Practices for Canada Thistle."
    Purdue University, Department of Botany and Plant Pathology.

    Espalier - An Art Based on Science

    Karl Foord, UMN Extension Educator



    Espalier is a plant shaping/pruning method where plants are grown in a single plane limiting their height and width to a defined area. The area is usually defined by a permanent framework which stabilizes the plant. The espalier is developed and maintained by pruning techniques of which timing is a critical part, for a pruning cut made in early spring will likely have different results than one made in midsummer.


    Role in the Landscape

    Espalier takes on a number of high profile roles in the landscape. It can be the focal point of the landscape design or take on lesser roles as privacy screens or backdrops. It can function as a key plant softening the appearance of walls or act as an accent or specimen plant. An accent plant has year around interest like most evergreens. A specimen plant has seasons of interest such as flowering, fruiting or attractive bark. Because the espalier technique reduces the number of leaves on a plant, the stems, bark texture, leaf shapes, flower and fruit are more exposed and emphasized. Due to its spatially defined nature, espalier makes efficient use of space and permits a greater variety of plants than if full sized plants were used.

    Espalier is a gardening technique of long standing. It has been practiced in gardens of Egyptian Pharaohs, middle age monks, and French kings. One of the more famous locations where espalier is on display is at Claude Monet's garden in Giverny, France (Exhibit 1 & 2).

    Espalier techniques

    Mastering espalier technique involves understanding how the plant responds to pruning cuts and shape manipulation. It involves choosing the buds one wants to form the branches that will create the desired shape. At least four techniques are essential to success.

    The first involves cutting and bud orientation. When a terminal bud is cut, its hormonal inhibition of buds down the stem is released and the cut stem establishes many branch point s (Exhibit 3). The idea is to make the cut above the bud facing in the direction you want the stem to grow.


    The second involves knowing how to bend a branch. Branches should be bent when they are young and most supple. The best way to proceed is to attach the branch to a splint prior to the bend (Exhibit 4) and bend the branch over a few weeks time, adjusting the angle of the branch 5-10° at a time (Exhibit 5). Care should be taken to not girdle any stem with plant ties and to move them annually if necessary.



    The third involves maintaining the plant within the proscribed limits by precise pruning of the branch laterals and sub-laterals (Exhibits 6 & 7). This serves to limit the length of stem growth, and encourages the development of fruiting spurs.



    Fourth involves eliminating unwanted buds through the technique of rubbing. Should a bud exist in a place where a stem is not desired, the bud is removing by rubbing it off the stem (Exhibit 8).


    An example of an espaliered apple (Exhibit 9) as well as many other plants can be observed at the Landscape Arboretum.


    Want to know more?

    This article is by necessity a very basic introduction. A very helpful book on the technique is, Espalier: Essentials of the Candelabra Pattern by Katherine Aby. Espalier can be appreciated and understood from books but, espalier techniques are truly learned and developed by practice. There will be an opportunity to observe and practice next month. Katherine will be teaching a one day class on the basics of espalier on Wednesday, June 15 to interested parties. Location will be based on # of registrants being either in South Minneapolis or closer to the Arboretum. If you are interested please contact Katherine at:

    Special thanks to Katherine Aby for the use of her illustrations. More illustrations and a more detailed discussion of techniques can be found in her book, which can be obtained on her website .

    Spring Pruning Tips for Woody Landscape Plants

    Kathy Zuzek, UMN Extension Educator, Horticulture

    Photo 1-1.jpg

    Photo 1:Rodent damage girdled these stems. K. Zuzek, UMN Extension.

    Many shrubs are planted in landscapes for their wonderful floral display. One of the few shrubs that have bloomed to date during this slow-to-arrive spring is forsythia. With masses of yellow flowers, forsythias are wonderful plants in the spring landscape. But cultivars with appropriate flower bud hardiness for use in Minnesota are large shrubs with rapid growth rates. Their ability to quickly produce large quantities of upright and arching stems that tangle together to produce an unkempt-looking plant turns them into aesthetic liabilities in the landscape after blooming. Consistent pruning is the solution. Enjoy the floral display but remember that if you have reason to prune your forsythia, pruning should happen immediately after bloom.

    Like many of our shrubs that bloom in early spring, forsythias produce flower buds on previous years' stems. To enjoy maximum bloom on these shrubs both this year and next year, it is important to prune these plants immediately after flowering stops this spring. This allows enough time for plants to produce stems during the 2011 growing season that will house next year's flower buds. A list of shrubs that bloom on previous years' wood can be found at

    You may also need to prune shrubs this spring because of damage that occurred during winter thanks to rodents, rabbits, and low winter temperatures.

    Mice and voles were busy under the snow line this winter stripping bark at the base of shrubs and young or thin-barked trees (Photo 1). Rabbits can create the same kind of injury by stripping bark above the snowline. If this feeding removed bark completely around stems and trunks, plants are effectively girdled and stems and trunks will die above the point of girdling.

    Photo 2-1.jpg

    Photo 2: Winter injury of rose canes. K. Zuzek, UMN Extension.

    Most deciduous shrubs have the ability to produce new shoots from their crowns or from roots. Prune off the girdled stems this spring and new shoots will replace the damaged stems over the next few years. On the other hand, the best course of action for a completely girdled tree is removal and replacement with a new tree. Many trees sucker below girdling damage. Many trees are also produced through grafting or budding onto rootstocks. Suckers from below the graft union that are trained into a new tree will give you a different (and probably undesirable) tree than the one you started with.

    Rabbits will often clip entire stems off of deciduous shrubs as they feed during winter. If this browsing injury left you with irregularly shaped shrubs and stems of widely different heights, you may want to prune these plants to recreate their natural plant habit. Entire stems can be removed at the base to allow growth of new replacement stems from the crown or roots. Or stems can be pruned back to ¼" above a bud that will direct growth in a desirable direction as the bud expands and grows. Make this pruning cut at a 45° angle with the high point of the cut directly above the bud.

    Winter injury should also be removed from woody plants this spring. Shrub roses are a prime example of this. Many repeat flowering shrub roses experience extensive cane mortality due to low winter temperatures. The injury is very evident in spring. Dead canes will be brown or black and there will be no actively expanding buds. Healthy canes can be green, red, or brown (depending on cane age and cultivar) and you will see buds along these canes actively expanding and growing in spring (Photo 2). Often low winter Photo 3-1.jpg

    Photo 3:Sap bleeding from pruning wound. K. Zuzek, UMN Extension.

    temperatures kill canes protruding above snow while the bases of canes covered by snow are not injured. Find an outwardly facing bud in the live portion of canes and prune canes back to ¼" above this bud using the 45° angle cut mentioned above. If canes are killed to the base, remove them completely and new canes will develop from the crown and roots of the plant.

    As you prune woody plants in spring, you may see sap oozing from pruning wounds (Photo 3). This may continue for several days and happens to varying degrees on many trees and shrubs. It is most noticeable on trees because pruning wounds are larger and are at or above eye level. This oozing or "bleeding" occurs when increasing temperatures in spring activate enzymes that convert the starches that store energy in plants into sugars that can be easily transported throughout the plant. As starches are converted into sugar, water movement is initiated upwards in stem and root xylem tissue due to differences in sugar concentrations throughout the plant. Pressure increases in the plant and this pressure Photo 4-1.jpg

    Photo 4: : Oak wilt fungal spore mat. J. O'Brien, USDA FS ,

    results in the "bleeding" from new pruning wounds. Bleeding can be unsightly but is not harmful to the plant. It actually signals active cell activity and a rapid pace of wound healing.

    Remember that oak trees should not be pruned in April, May, or June. Sap feeding beetles of the Nitiduldae family are the insects commonly responsible for long-distance movement of fungal spores that lead to new infection centers of oak wilt. The beetles are attracted to both fresh wounds (like a pruning cut) on oak trees and to the fruity smell of the fungal spore mats produced in April, May, and June on oaks infected with oak wilt (Photo 4). As they visit the mats, they pick up spores that can be transferred to a fresh wound on a healthy tree. As these spores infect the tree, oak wilt occurs.

    You buy a plant at a garden center. Where did it come from?

    Karl Foord, UMN Extension Educator


    Vanilla Strawberry™, Hydrangea paniculata 'Renhy'PP20,670

    To answer this question I traveled to Newport, Minnesota to visit with Debbie Lonnee who is a Planning and Administration Manager at Bailey Nurseries. Don't be fooled by the title, Debbie knows hers plants intimately. Listening to her describe plant cultivars is like watching Monet paint.

    Bailey Nurseries

    Bailey Nurseries celebrated its 100 year anniversary in 2005 and is still managed by fourth generation members of the Bailey family. Bailey has production locations in Minnesota, Illinois, Iowa, Oregon, and Washington where it produces and distributes fruit and shade trees, ornamental shrubs and vines, roses, evergreens, fruits, perennials, and annuals. As a wholesale operation they sell to over 4500 retail garden establishments, landscapers, and growers located in 47 U.S. states as well as Canada, Europe, South Africa, Australia, and Japan. Try to imagine the effort involved in getting this wide variety of plants delivered bellaanna.jpg

    Bella Anna™ Hydrangea arborescens 'PIIHA-1' PPAF

    at the right time of year for each of these locations. It boggles the mind.


    Endless Summer® Blushing Bride™ Hydrangea, Hydrangea macrophylla 'Blushing Bride' (PP17,169).

    Breeding efforts and partnerships

    The breeding efforts focus on improved habit and ornamental qualities, and disease resistance to name a few among a host of characteristics. The disease resistance objective is particularly noteworthy as its goal is to eliminate chemical treatments and to replace plants which have been shown to be particularly susceptible to diseases. Bailey has a breeding program but they do not restrict their efforts to their own program, as they solicit breeding partners from around the world. This greatly increases their reach and at the same time increases our exposure to newly produced plants. To get a sense of how this brings plant opportunities to you and me, I asked Debbie to trace the development of three new cultivars.

    New Cultivars

    One of the new cultivars is 'Vanilla Strawberry™' which is a Hydrangea paniculata with conical shaped flower. The interesting thing about this cultivar is that the flower starts out stark white and gradually changes from white to pink from the bottom up. This cultivar came from a partnership with SAPHO, an organization formed between French breeders and the Angers branch of the French Research Institute (INRA). Presently there are 20 breeder/stockholders including M. Renault, the breeder of 'VANILLE FRAISE ® 'Renhy'.


    Twist-n-Shout® Big Leaf Hydrangea, Hydrangea macrophylla 'PIIHM-I' PP20,176

    Another new cultivar is 'Bella Anna' which is a Hydrangea arborescens from the Endless Summer® series of reblooming Hydrangeas developed by Dr. Michael Dirr who spent most of his career at the University of Georgia. 'Bella Anna™' produces giant pink flowers that can measure up to 10 inches across. It is in essence a pink 'Annabelle' hydrangea.

    It should be noted that H. arborescens does not change flower color in response to soil pH. The three other cultivars in the Endless Summer ® collection (Endless Summer™, Blushing Bride™, and Twist-n-Shout™) are all H. macrophylla species which does respond to soil pH. There are products called Color Me Pink™ and Color Me Blue™ which will change the color of your hydrangea flowers. The flowers become Pink in alkaline soil (pH greater than 7), and blue in acidic soil (pH less than 7).

    A third cultivar is 'Little Devil™' Ninebark which is a Physocarpus opulifolius. This cultivar was bred by Dr. David Zlesak who was the previous editor of the Yard & Garden News and now a professor at the University of Wisconsin-River Falls (UWRF).
    One of the advantages of this cultivar is its size. David was able to introduce a dwarfing gene creating a 4 foot tall dark leaved ninebark vs. a 10 foot tall 'Diablo' dark leaved littledevil.jpg

    First Editions® Little Devil™ Ninebark Physocarpus opulifolius 'Donna May' PPAF

    shrub. Much of today's breeding work focuses on creating small stature or dwarf varieties. This permits traditionally larger plants to fit into today's smaller landscapes as well as permitting a greater variety of textures, forms and colors for the landscape palette.

    Last spring Twin Cities Live did a short segment on Bailey Nurseries, in which they showed a number of the production systems and facilities. This video is no longer available.

    All photos courtesy of Bailey Nurseries.

    Edible Landscape Wrap-Up

    Emily Tepe, University of Minnesota Research Fellow, Department of Horticultural Science

    After many weeks of harvesting mountains of chard, tomatoes, zucchini, peppers, cucumbers, raspberries and a multitude of other vegetables, fruits and herbs, the University of Minnesota Edible Landscape has been put to bed. Well...almost. The few lone stands of silvery blue kale seem to mock the cold, their leathery leaves sweetening with each frosty night. And many of the herbs are even holding onto their green. Other than those, the Edible Landscape is now resting after a long and productive season. snow on kale_tepe.JPG

    Photo 1 (left and above): Snow on dinosaur kale in the University of Minnesota Edible Landscape on October 12, 2009. Emily Tepe.

    If you haven't had a chance to see the gardens on the St. Paul campus this year, and if you haven't been following the Edible Landscape blog, here's a rundown of some of the details of the project. The Edible Landscape filled four beds outside the Plant Growth Facilities on Gortner Ave. The 1500 square foot garden was comprised of 75 varieties of fruits, vegetables, herbs and flowers. The garden was designed to emphasize the ornamental qualities of edible plants, and demonstrate how these plants might be incorporated into the home landscape in creative, attractive ways. Most of the ornamentals, herbs and warm season crops were started from seed in the greenhouse during the winter months. Others, such as chard, kale, summer and winter squash, melon, lettuces and radishes were direct seeded throughout the season. By mid-October, almost 500 pounds of produce had been harvested from the Edible Landscape and shared with students, faculty and staff in the Department of Horticultural Science.

    After cleaning all the annuals out of the garden (which were then composted), winter rye seed was raked into the beds for a winter cover crop. It may sound strange to think of cover crops in a home gardening demonstration. After all, we normally think of cover crops being used on acres of land, not in the backyard. But cover crops in the home garden can offer great benefits such as weed suppression, erosion control, increased microbial activity and moisture retention, just to name a few. You can read about Green Manure Cover Crops for Minnesota on the U of MN Extension Website.


    Photo 2 (right and above): The largest bed in the University of Minnesota Edible Landscape in mid-July. Emily Tepe.

    If the idea of edible landscaping sounds intriguing, or if you would simply like to learn more about this project, visit the Edible Landscape blog. The entire season was documented on the blog, which is filled with photos, design ideas, plant lists, growing information and more. Now that the harvests have finished, and the season is being evaluated, there will be more discussions on the blog about plant combinations that worked well, successful varieties, and lessons learned. Read, learn, share and join the discussion.

    Wealth of Education Found in the Display and Trial Garden

    Emily Tepe, Research Fellow, Department of Horticultural Science

    10-1-09ediblelandscaping_emilytepe.JPGIf you walk through the St. Paul campus Display and Trial Gardens these days you're bound to see a lot of activity. No, I'm not talking about bees on the flowers (although there were a lot of those with the unusual warm weather in September), I'm talking about students. With the start of the fall semester comes a plethora of courses on plant identification, propagation, diseases and insects. The Display and Trial gardens offer a convenient and valuable living laboratory for these courses. In fact, throughout the year (save for a couple of months in the depths of winter) these gardens offer education to many people in the University community and beyond.

    Photo 1 (left): Edible landscape portion of the University of Minnesota Display and Trial gardens. Emily Tepe

    An Inspiring Outdoor Classroom

    The Display and Trial gardens are comprised of various areas between Alderman Hall (home of the Department of Horticultural Science) and the Plant Growth Facilities on Gortner Avenue. Trees, shrubs, and hardscaping create the foundation for the gardens, and break it up into beds, each with their own theme. These themes change from year to year as new varieties are introduced, student projects are realized, and interesting gardening styles bring an opportunity to explore and experiment. The 2009 season brought some inspiring plantings and great educational opportunities.

    These educational opportunities often get started while there is still snow on the ground, as students propose projects for the garden and begin designing beds and planting seeds in the greenhouse. Classes ,such as Professor, Neil Anderson's Floriculture Crop Production, research and schedule their assigned crops, working backwards from the planned finish date (mid-May), to assure their annual flowers are at the perfect stage for judging before being planted out in the gardens. Many of the varieties they grow are trials for major seed companies.

    When spring arrives, students who have proposed projects for the gardens, begin breaking ground, laying out beds, sowing seeds, and eventually setting out transplants. They are responsible for maintaining their plantings throughout the season, keeping the beds watered, weeded and looking good. It's a great experience for students to take what they've learned in the classroom and put it all into practice. These projects bring the fresh ideas of students to the forefront, allowing them to experiment with new concepts and interesting designs, and even showcase some of their research.


    By the time the gardens are in full swing, the St. Paul campus is pretty quiet. Most of the student body is gone for the summer, and the gardens become an inspirational outdoor venue for summer camps, youth enrichment programs, Master Gardener events, and horticulture industry field days. 

    Photo 2 (right): Master Gardeners tour the Edible Landscape at the University of Minnesota State Master Gardener Conference. Emily Tepe

    On any given summer day you are bound to find a group of high school students cutting flowers for a design and marketing program, or a flurry of youth in matching t-shirts tending a plot of vegetables; kept on task by their nurturing and enthusiastic mentors. Members of the local community often visit the gardens to view the new varieties released by the University, the vast array of annual flowers, and the creative ideas such as this year's Edible Landscape.

    A Living Laboratory

    10-1-09PlaPathclass_EmilyTepe.JPGOnce classes start in September, University students begin spending a lot of time in the gardens. Many of the students in the introductory horticulture courses have never seen some of these plants before, and the gardens offer a close-up look at the topics they're studying. Tom Michaels, professor in the Department of Horticultural Science (teaching Plant Propagation this semester) said of the Edible Landscape portion of the gardens, "Students pass right by those beds every time they come to lab. They can't help but see examples of the food they buy in the produce department actually growing in front of them. It gives me the opportunity to talk about those foods and encourage them to stop by the beds and find examples of how chard differs from lettuce or dinosaur kale, or similarities and differences between beans and peas". The gardens are indispensable for the plant identification courses as well. Students find examples of hundreds of species, and with hand lenses and forceps, can scrutinize tiny flower parts to determine the plant family to which they belong.

    Photo 3 (above): Plant pathology students observing symptoms of apple scab in the Display and Trial garden. Emily Tepe.

    Horticulture students aren't the only ones spending time in the gardens. The Display and Trial Gardens provide a wonderful laboratory for plant pathology and entomology students as well. Todd Burnes, scientist in the Department of Plant Pathology, said numerous courses spend time in the gardens identifying and studying various plant diseases. While in the home garden, powdery mildew, leaf spot and white mold would likely prompt immediate action, here we aren't so hasty. The opportunity for students to observe the symptoms of diseases, collect samples and study them in the lab is worth a few ugly plants here and there at the end of the season. Entomology students roam the gardens, sweeping their longs white nets along the edge of the prairie strip, or carefully trapping unsuspecting insects on the zucchini flowers. Once back in the lab, they'll identify and study their specimens.

    Photo 4 (below and right) : Powdery mildew on zinnias in the Display and Trial Gardens. Emily Tepe.10-1-09_Med_powderymildewonZinnia_EmilyTepe.JPG

    It is truly amazing the wealth of education that can be found in a garden. Here on the St. Paul campus, the Display and Trial gardens offer many people a chance to get up close and personal with flowers, grasses, trees, fruits and vegetables. And whether in class or just wandering through, there are countless opportunities to discover. Every garden offers such opportunities for young and old alike.

    You are invited! Come and join us for our 2nd Annual Hennepin County Master Gardeners Learning Garden Tour. We have 10 very unique gardens designed and maintained by Master Gardeners for you to enjoy. The Master Gardener homeowner and other Master Gardeners will be on site to respond to your questions. For a preview of some of some of the gardens and event please view this video.

    Each garden has a different theme and demonstration. Themes include a fairytale garden, a low maintenance garden, urban and woodland retreat gardens, a farmhouse in the city, container gardening, a sanctuary garden, and a shade garden with a labyrinth. There will be practical, informative demonstrations at each site. Master Gardeners will conduct interactive demonstrations at 10, 12, and 2 p.m. on a wide range of topics. You can learn how to create small space, container, and vertical gardens, build low maintenance water gardens in a weekend, create garden rooms and rain gardens, using color to create moods, and how to grow vegetables.

    Thousands Visit Morris Bedding Plant Trials


    Steve Poppe, University of Minnesota Scientist, West Central Research and Outreach Center

    In the past, no other segment of the floriculture production industry has enjoyed public interest and use of its product more than bedding plants (annual flowering plants). Bedding plants are an indispensable item for landscape use, presenting an array of flowers and foliage that add color and texture to the landscapes of homes, apartment complexes, shopping malls, public buildings, city streets and parks.

    The University of Minnesota supports this growing industry through annual flower trials conducted at Morris, St. Paul and Grand Rapids. In 2008, we evaluated annual flowers from eighteen major plant companies. Our gardens are open to the public and industry for selfguided tours throughout the growing season, providing a unique opportunity to compare performance of bedding plant cultivars under regional conditions. The public's response to the 2008display gardens at all locations was very positive. Several thousand people visited these sites during the summer. Numerous educational programs and garden tours were provided at all sites, highlighting the outstanding annuals in our trials.


    This special weekend features an information fair and water-wise demonstrations, art activities, music and a Heart of the Beast Puppet Theatre performance! Part of the 2009 Waterosity theme, this special weekend brings together additional resources and events surrounding the theme of water usage and water-wise practices. Here are just some of the special highlights:

    The renowned In the Heart of the Beast Puppet and Mask Theatre will present Are You Thirsty?" (11 a.m. & 1 p.m. July 11 & 12).

    Performances will be free with Arboretum admission.

    Volunteers will be on hand to help showcase the various exhibits

    The information fair will include several area industry and non-profit groups that are involved in water use and management.

    While at the Arboretum, don’t miss all the great art displays dispersed throughout the grounds. The over a dozen special art displays celebrating Waterosity will be in place through early October. Artists far and wide submitted ideas this past year for consideration and a subset were selected for implementation. Here are just a couple highlights!

    Water-Wise Gardening


    Julie Weisenhorn and Kathy Zuzek, Director, University of Minnesota Master Gardener Volunteer Program & University of Minnesota Extension Educator

    Watering your garden and lawn… it seems so straight forward. When the soil is dry or a plant wilts, water. If it doesn’t rain for two weeks, water. If you happen to have the hose on, sprinkle on a little water.

    Not so. There are many factors – the type of soil and the amount of sun and wind in your yard, the types of plants that you grow, weather patterns, and your cultural practices – that play into a landscape’s water needs. The water-wise gardener considers and plans for these factors to produce beautiful landscapes while minimizing water use.


    Jonathon Hensley, University of Minnesota Graduate Student

    The dense, accelerated pace of modern urban development has affected many of the earth’s natural processes. Asphalt and concrete rooftops, roads, and parking lots cover up to seventy percent of land area in dense cities like New York, while open space in sprawling cities like Phoenix, Arizona is lost to development at a rate of 1.2 acres per hour.1

    Approximately 1.5% of the continental United States, an area roughly equivalent to the state of Ohio, was covered by impervious surfaces in 2004.2 This percentage continues to grow and can be as high as 75% in urban areas. Of those impervious surfaces (not allowing the permeation of water), roofs can constitute a significant percentage. Such growth in impervious surfaces can result in a variety of environmental impacts including reduced aquifer recharging, overwhelmed storm water systems, urban heating, decreased surface water quality, and increased air ozone and particulate concentrations. These negative environmental effects impact residents and municipalities by affecting: clean water availability, storm water and sewage infrastructure costs, decreased runoff water quality, decreased employee productivity, decreased wildlife habitat, and increased operating costs of buildings through increased heating and/or cooling costs. Alternative solutions to traditional impervious building methods are being sought in order to mediate these negative environmental impacts and reestablish the green spaces desperately needed in our metropolitan spaces.

    Tips for creating successful window box planters


    David C. Zlesak, University of Minnesota Extension Educator

    The popularity of creatively combining different plant materials in window boxes has soared in recent years. Combining plants of various color, texture, and plant habit to design what in essence become miniature landscapes provides gardening enjoyment from both outdoor and indoor vantage points.  Designing and having window boxes can become a very fun, creative, and rewarding endeavor. The diversity of plant materials to choose from and effects that can be generated seem almost limitless.  Many people choose to try different combinations and overall themes each year.  This makes it exciting for neighbors and passersby as they anticipate what will be next.

    Rain Gardens


    Eleanor Burkett, University of Minnesota Extension Educator

    Whether you live in the city or reside on a lake or river shore, managing stormwater runoff is worth considering for your landscape. Rooftops, roads, driveways and sidewalks create hard impervious surfaces which rainwater and melting snow cannot penetrate through to soak into the soil. Additional runoff created by impervious surfaces often is channeled into depressions on your property, often eroding soil along the way. The additional runoff also increases the amount of nutrients and sediment that are carried into lakes, rivers, and wetlands.

    Simply put, a rain garden is a shallow depression filled with plants designed to collect rainwater runoff and allow it to filter into the soil, removing nutrients, sediments and other pollutants before reaching the groundwater. Small shrubs, flowering plants and ornamental grasses within a rain garden absorb nutrients, and the sediments settle to the bottom. Rain gardens add beauty to the landscape and may attract butterflies and birds.

    Waterosity Comes to the Arboretum


    Carolin Dittmann and Kathy Zuzek, Owner of Verbena Design and Landscaping and former University of Minnesota Former Graduate Student and University of Minnesota Extension Educator

    Water is the essence of life.  All living beings on earth depend on water for survival.  Water is also a source of joy and beauty.  Here in Minnesota with our 10,000 lakes, the headwaters of the mighty Mississippi, and the beauty of Lake Superior and the rivers that cascade into it, it is easy to celebrate the beauty of water.  It is also far too easy to ignore how wide-reaching our impact on water resources is.  From agricultural and industrial uses that benefit everyone to our individual use of water in our daily lives, we all consume and pollute water.  All of us – individuals, communities, and agricultural and industrial enterprises – need to act with wisdom and stewardship to manage and conserve our water resources, ensuring that safe water will be available as a source of delight and health today and in the future.

    David C. Zlesak, University of Minnesota Extension Educator
    Photo 1: Golden hakone grass has been a faithful perennial in this St. Paul garden for several years. David Zlesak

    Since 1990, the Perennial Plant Association (PPA) has sponsored the Perennial Plant of the Year® program. Each year members select a superior performing perennial to highlight and promote. Nominations are made by members and winners are decided by ballot. Criteria for nomination includes it must perform well across a wide range of climates, be widely available and easy to propagate in order to supply demand, be relatively low maintenance and easy to grow so the average gardener has a high likelihood at being successful with it, and the plant displays ornamental appeal over a long portion of the growing season.


    Photo 1: The Minnesota Green Expo will have hundreds of vendors representing a wide diversity of products. David Zlesak

    The Minnesota Green Expo is one of the largest Horticulture Expos in the nation. It is geared towards all sectors of the Horticulture/Green industry (arborists, florists, nurseries, greenhouses, landscapers, turf specialists, groundskeepers, etc.). It is a wonderful opportunity to learn through educational seminars, networking, and seeing new products at the huge tradeshow where regional, national, and international vendors are represented. Many nurseries have forced into growth and flower their new and recent cultivar releases and landscapers have beautiful displays demonstrating their products and skills.

    The Minnesota Green Expo is hosted jointly by the Minnesota Turf and Grounds Foundation and the Minnesota Nursery and Landscape Association. Although geared towards conveying information and highlighting products for industry professionals, it is a great opportunity for everyone who loves horticulture and wants to learn about the latest issues and products. To learn more, please visit: There are a lot of options to come and participate. One can purchase a three day complete registration (open to educational seminars and tradeshow), single day registration (open to educational seminars and tradeshow for the particular day), or tradeshow only access. With the event soon upon us, one can take advantage of the opportunity to just register at the door. The most affordable way to participate in this event is Friday only tradeshow access for $5.

    Landscapes with Healing in Mind

    Jean M. Larson, Program Manager of the Center for Therapeutic Horticulture at the University of Minnesota Landscape Arboretum

    If you are a gardener, or a nature enthusiast at any level, you already know the healing power of plants. Anecdotal evidence, personal experience and common sense support the fact that being around natural environments helps most people feel better. But what does science tell us about the healing power of gardens and landscapes?

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