University of Minnesota Extension
http://www.extension.umn.edu/
612-624-1222
Menu Menu

Extension > Yard and Garden News > Archives > April 2012 Archives

April 2012 Archives

Frost Protection of Blueberry Flowers

Karl Foord - Extension Educator, Horticulture

Irrigation serves to protect blueberry flowers from frost damage.

Here are some pictures - explainations to follow:

Brad Munsterteiger

Photo 1: Frost protection of blueberry flowers by irrigation

Brad Munsterteiger

Photo 2: Frost protection of blueberry flowers by irrigation

Brad Munsterteiger

Photo 3: Frost protection of blueberry flowers by irrigation

Contents April 15, 2012

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)

The University of Minnesota Extension Master Gardener Program is exploring the marketability of a new online gardening education series. The goal of this new education series is to provide home gardeners with a self-directed, online class series that provides basic, foundation education about best practices in gardening.

We would very much appreciate your participation and insights. Would you please complete this short survey related to your experience and interest in gardening, your opinions about the new course offering, and basic demographic information.

Your answers are anonymous and your participation in the survey will help with the development and marketing of this course. The survey will take less than ten minutes.

If you have any questions about the survey please contact Daniel Jones-White at djwhite@umn.edu.

Survey on Online Gardening Education Series

Karl Foord - Extension Educator, Horticulture

While exploring the Minnesota Landscape Arboretum I encountered Dr. Stan Hokanson the woody plant breeder in the Department of Horticulture Science. He introduced me to the Clove Currant (Ribes odoratum). The odoratum nomenclature is well deserved. Clove Currant give off a very pleasant spicy fragrance hinting of clove and alspice (Photos 1 and 2). The plant has yellow flowers and a corolla long enough to restrict its pollinators to those with long tongues like bumblebees (Photos 3 and 4).

Another tree with fragrant flowers is the Korean crabapple (Malus bacatta jackii) one of the earlier flowering crabapples. The flowers are being visited by native bees (Photos 5 and 6).

Karl Foord

Photo 1: Clove Currant (Ribes odoratum) flower close-up

Karl Foord

Photo 2: Clove Currant (Ribes odoratum) flower

Karl Foord

Photo 3: Bumblebee showing long tongue required to reach nectaries on Clove Currant

Karl Foord

Photo 4: Bumblebee pollinating Clove Currant

Karl Foord

Photo 5: Native bee (Andrena ssp.) on Korean crabapple (Malus baccata jackii)

Karl Foord

Photo 5: Native bee on Korean crabapple (Malus baccata jackii)

Frost Damage to Apple Flowers

Karl Foord, Extension Educator, Horticulture

Temperatures in the mid to low 20's were encountered last Tuesday April 10th in many parts of central and southern Minnesota. Apple fruit flowers are damaged at temperatures lower than 28 degrees F. depending on the stage of the flower bud and the length of time at the low temperature. The more open the flower bud the more susceptible the bud is to low temperature damage.

The following picture gallery shows the types of frost damage experience by apple flowers in Chaska, Minnesota. The gallery begins with heathy flowers with green stigmas and cream anthers, shows partially damaged flowers with dead stigmas and soom dead anthers, and finally a flower will all parts killed.

Karl Foord

Photo 1: Healthy Apple Flower

Karl Foord

Photo 2: Healthy or partically damaged apple flower

Karl Foord

Photo 3: Totally damaged flower top left and partially damaged flower bottom right

Karl Foord

Photo 4: Frost killed apple flower with brown stigmas and anthers

Karl Foord

Photo 5: Frost killed apple flower with brown stigmas and anthers

Contents April 1, 2012

Karl Foord, Extension Educator - Horticulture

Bulbs

Click any image below to open a slideshow.

Karl Foord, Extension Educator - Horticulture

Click any image below to open a slideshow.
Trees

Many tree flowers are described as inconspicuous. This may be more a matter of size and location. Tree flowers tend to be shhort lived, inaccessible if higher up in the tree, and smaller than many of our showy garden flowers. On closer iinspection you may find them to be rather intreguing. Consider the first photo of Autumn blaze Maple.

A Range of Colors - Pollen

Karl Foord, Extension Educator, Horticulture

I was photographing honeybees working an early pollen source last spring - Allium Allium christophii 'Star of Persia' (Photo 1).



Karl Foord


Photo 1: Honeybee on Allium christophii 'Star of Persia'


I noticed that the pollen carried by the honeybee was an interesting grey color. This led me to wonder about pollen colors. I did some research and came up with a dizzying array of pollen colors represented in Table 1).

Karl Foord

Table 1: Chart of Pollen Color of Some Selected Plants

Photo 2 shows a bumblebee with the off white pollen of Sedum.

Karl Foord

Photo 2: Bumblebee on Showy Snowcrop Sedum sieboldii 'Star of Persia'

As spring approaches keep an eye out for the array of pollen colors offered by our spring flowers (Photo 3) and carried by our insect pollinators (Photo 4).

Karl Foord

Photo 3: Scilla siberica Siberian Squill with blue pollen

Karl Foord

Photo 4: Honeybee working Scilla showing corbicula or pollen basket with blue Scilla pollen

Overwintering Insects in Homes During Spring

Jeffrey Hahn, Asst. Extension Entomologist

Throughout March, people have been having problems with nuisance insects in their homes, especially cluster flies, boxelder bugs, and (multicolored Asian) lady beetles.  Fortunately, these insects are harmless, although they can be annoying, especially when a lot of them are present.  Here are a few things to keep in mind when dealing with these insects.

First, it is important to know that these insects are not reproducing indoors.  Because they emerge from their hiding places periodically throughout the winter and early spring, it appears they are laying eggs and their offspring are emerging.  In fact, all of the insects you see now entered your home last fall.  They hibernate in balls or clusters in wall voids, attics, and similar areas.  As the temperatures warm, the insects in the outer layers become active first and then emerge into the living quarters of the home, explaining why they do not all become active at the same time.

Gail Felton

Photo 1: Multicolored Asian lady beetles

Because they are emerging from hidden sites, it is not practical to treat them to prevent their emergence.  Once they are out in the open, your best bet is physical removal, such as vacuuming.  Eventually, all of these overwintering insects will become active and move away from their overwintering sites.  Fortunately for those trapped in homes, they are short lived

To minimize these kind of problems in the future, it is important to treat these insects in the fall as they are first trying to enter your home.  This is a two pronged approach.  First it is important to inspect the outside of the home during summer and seal spaces and gaps that may be used by these insect to get inside.  This should be followed up with an insecticide application in the fall, just as these insects are trying to get inside.  It is not possible to prevent all nuisance insects from entering into a home, but you can reduce the number that do causing fewer problems later during the winter and spring.  You can find more information here on cluster flies, boxelder bugs, and lady beetles.
  • © 2014 Regents of the University of Minnesota. All rights reserved.
  • The University of Minnesota is an equal opportunity educator and employer. Privacy