Extension > Yard and Garden News
Karl Foord, Extension Educator - Horticulture
One of the factors in the decline of pollinators is the loss of habitat. To get a sense of this I took the position of a bee looking for forage. I drove my car from my house through my neighborhood in Chaska, Minnesota around the Chaska Middle School out to Hwy 41 and north toward Hwy 5 and the Minnesota Landscape Arboretum.
What I found in this casual survey was a preponderance of turf in the landscape. The homes had most turf surroundings with a few shade trees and low maintenance foundation shrubs. There were a few flowers to accent a rock or a mailbox. Often these plants were not attractive to pollinators such as daylilies. The businesses had turf and accented their signs with rocks and low maintenance plants. The industrial area was completely dominated by turf and shade trees, and contained no cultivated flowers.
The place where I found bee forage was in refuse areas or undeveloped areas. Here I found typical weeds such as thistle (Cirsium spp.), Queen Anne's Lace (Daucus carota), Bird's Foot Trefoil (Lotus corniculatus) among others. I also found Wild Bergamot (Monarda fistulosa), Hoary Vervain (Verbena stricta), and Grey-headed Coneflower (Ratibida pinnata). The majority of bees including bumble bees and other natives were working the beebalm and the vervain, predominantly.
Incidently the richest area was the undeveloped area along Hwy 41. I was informed that this was destined to be developed.
As a bee searching for forage this is rather discouraging with the future looking even more bleak. All things considered it still looks like one of the more promising solutions is to follow Dr. Marla Spivak's exhortation to plant flowers and specifically those that provide nectar and pollen to our pollinators.
There are many subtle and complex interactions between plants and their pollinators.
Can our combined urban spaces be designed in such a way as to substitute for the loss of natural areas as we humans continue to expand?
I do not know. However, it is in our best interest to try. As Marla says, "Plant Flowers!".
Jeffrey Hahn, Extension Entomologist
Photo 1: Fall webworms can detract from a tree's appearance but does little actual damage to it.
While most caterpillars are active during the spring, there are a few that are not feed until summer. Fall webworm caterpillars, Hyphantria cunea are first active during late July and can be found feeding into September. This caterpillar varies in color from pale green or yellow with two rows of black spots on its back with long fine white hairs.
However, an easy way to identify fall webworms is from the webbing they produce that covers the ends of branches. The caterpillars remain inside this webbing to feed on the leaves. The feed on a wide variety of hardwood trees (over 100 trees and shrubs), including black walnut, oak, birch, elm, ash, willow, cottonwood, and chokeberry.
Typically fall webworms attack large, mature trees and their feeding is minor and does not have any lasting effect on trees. Occasionally small trees are attacked; they can be severely defoliated and can even be completed encased by webs. The primary problem is to the appearance as the webbing can be unsightly. However, after fall webworms are done feeding the webbing eventually deteriorates and goes away on its own.
In the majority of cases, a fall webworm infestation can be ignored, especially if it is in a large, mature tree. Direct insecticide treatments are not effective as the webbing protects the caterpillars from sprays. It is possible to effectively spray fall webworms when the caterpillars first hatch and the webbing is still small, although people don't usually notice them then. If the webbing is within reach, it can be physically pulled out along with the caterpillars. Even if you don't get the entire webbing out, you can still knock many of the caterpillars out of the nest. Do not try to burn the webs; this is more harmful to trees than any control that is achieved.
Each year, the Minnesota Landscape Arboretum Education staff designs and plants a Teaching Garden on-site focused on programming about food with titles like "Veggies by the Yard", and "Grow A Healthy Handful". Interpretive signage is always important to provide walk-by learning to visitors. These programs and the signage as well as plant lists, construction details, and tips for teaching are made available as teaching materials to Extension Master Gardeners the following year.
With all the interest in protecting pollinators, coupled with the need for people to eat healthier, the "Smart Snacks" garden idea was born. It was trialed in the Teaching Garden (now called the Extension Master Gardener Teaching Garden), and this year was made available to Master Gardener volunteers. Five signs highlighting specific messages were made available as well - how tomatoes are pollinated, growing plants for pollinators, healthy tomato stats. Plant lists included cherry tomatoes, verbena, basil, mint, zinnia - and photos of examples as well as resources for materials. Smart Snacks gardens can be planted anywhere including in a "pop-up garden" format planted in a collapsible "bag" pot placed on asphalt or cement. The goal? To get people planting to support their own snacking and that of pollinators!
I chose to plant my own Smart Snacks garden along our driveway in two raised beds / retaining walls each about 48" x 72". I had started planting pollinator-friendly plants last year: swamp milkweed (Asclepias incarnata), native bee balm (Monarda fistulosa), gayfeather (Liatris spicata), coneflower (Echinacea angustifolia), purple dome asters, and others. Early spring flowers include pigsqueak (Bergenia cordifolia), lily of the valley (Corvallis), beard tongue (Penstemon) and big root geranium (Geranium maculatum). This spring, I added elderberry, anise hyssop (Agastache), more bee balm, cherry tomatoes, and saw the milkweed had spread.
The Smart Snacks garden is successful. A variety of bees - native, bumble, honey - as well as soldier beetles, monarchs, dragon flies, and moths come to roost and "snack" on nectar-rich plants and pollen. I, too, snack a bit on mints and cherry tomatoes, as I pass by. The best surprise were six monarch larvae on the swamp milkweed! I look forward to expanding my Smart Snacks garden annually into nearby beds.
For information on Smart Snacks gardens and planting for pollinators:
MN Landscape Arboretum: Smart Snacks Garden
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.
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.
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.
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.
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.
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").
We aren't always able to answer everyone's text'd questions on the air, so we try to post a few along with answers here in the Yard & Garden News blog. Remember that you can always visit the U of M Extension Garden website for loads of gardening resources.
Hope you join us and our host Denny Long every Saturday, 8-9am, on WCCO Smart Gardens and happy gardening!
From Dave in South St Paul: My tomatoes are flat and rotting on the bottom. What causes this? I water at the base and they are in containers.
Answer: This is a condition called "blossom end-rot". It is the result of calcium deficiency in the developing tomato fruit. This does not necessarily mean there is not enough calcium in the soil though - just that plant is unable to acquire it. This is due to environmental conditions such as fluctuations in soil moisture, heavy applications of nitrogen fertilizer, and injury roots.
Read more ...
Answer: It's typical for Curcubits varieties to cross-pollinate. They are in the same genus, they bloom at the same time and they are both pollinated by (usually) bees. Successful pollination produces a seed(s) and the tissue that surrounds it. It's important to note that this year's pollination will produce the seeds for next year's plants provided you save seed. Therefore, if you are planting seeds from a seed packet you purchased or transplants you purchased from a greenhouse, you should get the kind of squash / cucumber on the labeled. It's next year you may get a variation on the original seed due to cross-pollination.
Question: I have had some success wintering begonias. Do you have suggestions for more success?
Answer: When you bring plants indoors for the winter, take this opportunity check them thoroughly for insects and insect eggs especially under the leaves. Wipe / rinse leaves, remove any signs of insects like webbing, and remove/dispose of dead leaves and flowers both on the plant and on the soil surface. Transplant into a clean pot with new potting soil. If the plants are large, consider cutting the plants back about 1/3 to just above a leaf node (a node is the point where a leave grows from a stem). Water and place in a sunny window. Begonias do not do well when over-watered, so check the soil about 2" down with your fingers before watering (recommended for all houseplants). and water if dry. You may find plants that are brought in from the out of doors will drop leaves initially. Remove the dropped leaves and continue watering as usual. Wait to fertilize when new growth appears with a complete fertilizer - 10-10-10 (N-P-K) or similar - at half the recommended strength.
Question: We want to seed about an acre. What type of seed do we use that takes, grows fast, and makes a great grass?
Answer: Choose a grass variety based on your conditions (the amount of light, soil type, moisture level) and based on the kind of activities for which you plan on using the area (sports, low-traffic, play area). Here is a good resource: Turfgrass Selection for Sustainable Lawns
You'll see from the Upper Midwest Home Lawn Care for Cool Season Grasses calendar that mid-August to mid-September is the optimal time for seeding your lawn. Seeding in this time period provides cooler temperatures, encourages germination, and enables the grass seed to form healthy roots before gradually going dormant for winter.
Question: Plum tree loaded with fruit. When is the best time to prune so the branches are not on the ground?
Answer: A good problem to have! Support the plum branches with sawhorses, PVC pipe, or other sturdy braces. Harvest the fruit as soon as it is ripe to reduce attracting pests like yellow jackets or birds damaging fruit. Then prune the tree when it is dormant - March or early April in Minnesota. See Stone Fruits for Minnesota Gardens for specifics on pruning including diagrams. Extension also has a great publication on pest management for stone fruits here.
Question: My Hydrangea doesn't have any flowers on it yet. Do they bloom every year?
Answer: Hydrangeas that are hardy in Minnesota typically bloom every year. Factors that can influence blooming include:
- whether the plant is hardy in your zone (example: the Hydrangeas from a florist are not typically hardy for our landscapes);
- weather issues such as late frosts that affect flower buds;
- the amount of light the plant receives;
- pruning techniques - some people prune off flower buds unknowingly;
- whether the plant blooms on old or new wood;
- animal damage such as deer browsing.
Some Hydrangeas are just starting to bloom now too. Without knowing the kind of hydrangea and the care you have given it, it's hard to say why your particular plant isn't blooming. However, we have had numerous people ask why their Endless Summer Hydrangea looks healthy, but doesn't bloom or bloom well. Here are some reasons: Why my Endless Summer Hydrangea didn't bloom
From Paul Cherba: I am getting powdery mildew on my lilacs. Or something white. What can I do about that?
Answer: Common lilacs often get powdery mildew at this time of year due to higher humidity levels. It's typically more cosmetic than detrimental to plant health, and the spores are common and windblown, so there isn't a way to avoid it now or any action to take. Fungicides are available to spray. They are most effective if used at the onset of the mildew (see publication reference below).
Choosing plants that are resistant to pests like powdery mildew is the best option for minimizing its affect. Spacing plants according the their mature size and pruning to increase light and air circulation through the canopy / shrub also is helpful. Prune lilacs within two weeks of flowering before they set flowers buds for next year. Watering at the base of the plant will help keep plant leaves free of water droplets that can hold bacterial and fungal spores. More on powdery mildew on lilacs.
Question: My impatiens were beautiful and now they have been snipped of their leaves and flowers with only stalks left.
Answer: If the leaves have been eaten (they are not lying on the ground), then I would say it was rabbit damage or deer damage. If the leaves have dried up and fallen off the plant, you may have a disease such as impatiens downy mildew. This is a relatively new pest for Minnesota gardeners that affects shade-loving impatiens Impatiens walleriana (not New Guinea impatiens). White fluffy growth forms on the underside of the impatiens leaves. There is no cure and the plants should be removed. Avoid replanting Impatiens walleriana in the same bed. Read more here.
Question: I plan on planting an Autumn Blaze maple where my hackberry once was. When is the best time to plant this?
Answer: Planting a diversity of trees is really important. Trees provide shade, habitat for birds, animals and beneficial insects, and create canopies that cool our landscapes and homes - not mention being beautiful and valuable additions to our landscapes. Late summer / early fall is a good time for planting trees, so right now! Cooler temperatures mean less heat stress on the new trees. Here's a helpful Extension publication on planting trees. Good luck!