Honeybees in the Landscape

How to encourage and protect honeybees

By: Sandy Feather ©2010
Penn State Extension

Q. I have been reading about the recent problems with honeybees and was wondering if home gardeners can do anything to help them. Part of what I’ve read indicates that systemic insecticides like imidacloprid are responsible for the problem, yet I notice you recommend it from time to time in your column – aren’t there other products you could recommend?

A. Honeybee colonies throughout the United States and Europe are being impacted by a phenomenon now called colony collapse disorder (CCD). Beekeepers began reporting abnormally high losses in the winter of 2006. Researchers from Penn State’s Entomology Department have been studying the problem ever since. CCD is characterized by the mysterious absence of adult bees in or around hives, living or dead.

Honeybee colonies throughout the United States and Europe are being impacted by a phenomenon now called colony collapse disorder (CCD). Beekeepers began reporting abnormally high losses in the winter of 2006. Researchers from Penn State’s Entomology Department have been studying the problem ever since. CCD is characterized by the mysterious absence of adult bees in or around hives, living or dead.


Honeybee collecting pollen
Honeybee at work

In many cases, bee larvae and honey reserves, perhaps a few young adults and a queen are present, but the majority of adult bees seem to have vanished. Even more curious, the honey in hives that have been impacted by CCD is slow to be taken by other bees or animals that would typically rob an unprotected hive of its stores. Although similar “disappearances” have happened periodically since the mid-1800’s, the record level of losses now have made this a research priority for entomologists from across the country. Researchers estimate that one-third of honeybee hives in the United States have been wiped out by the phenomenon. Ice cream maker Haagen-Dazs is funding CCD research at Penn State and the University of California-Davis entomology departments because roughly 40 percent of the brand’s flavors come from fruits that depend on bee pollination.

The Perfect Storm

All of the research I have read to date points to a perfect storm of environmental, arthropod and disease factors that have resulted in CCD. Urban sprawl has reduced habitat for honeybees by replacing native flowering plants with exotic species that often do not produce pollen and nectar necessary to provide sufficient food resources. Lawns are routinely sprayed to control broadleaf weeds such as dandelions, and grasses do not provide the kind of pollen and nectar that supports bees. Hives that go into winter without sufficient food reserves (honey!) are doomed, especially wild hives that do not have a human keeper to supplement those reserves through lean winter months.

Tracheal & Varroa Mites

Additionally, tracheal mites and Varroa mites have been decimating beehives for decades. These mites are classified as spiders rather than insects, so beekeepers have used pesticides called miticides to control them in their hives. These products, as well as many classes of insecticides including products such as imidacloprid, have been implicated in CCD.

Bee Diseases

Honeybees are also susceptible to a number of fungal, bacterial and viral diseases. Colonies stressed by habitat loss, mites and pesticides are more susceptible to these diseases. A relatively new viral disease known as Israeli Acute Paralysis Virus has been identified in most CCD affected hives.

This swarm of honeybees was on the
move. Call a local beekeeper to
help them find a new home.

There are a number of things home gardeners can do to help honeybees including:

Plant a variety of flowering plants in your landscape – trees, shrubs, perennial and annual flowering plants. Having a variety of plants blooming in your landscape from early spring until late fall ensures a constant supply of pollen and nectar through the growing season. It is best to avoid double flowers because they produce little, if any, pollen. I have included a list of good bee and pollinator plants at the end of this article.

• Consider allowing “weeds” to flower in your lawn or a portion of your lawn.

• Minimize the need for pesticide applications by selecting plants that are resistant to common insect and disease problems that impact those species.

• When pesticide applications are necessary chose the least toxic product that provides effective control. Least toxic insecticides include horticultural oil and insecticidal soap that have no residual activity after the spray has dried and botanical insecticides such as pyrethrins and neem oil that have short residual activity, often breaking down within several hours of exposure to sunlight. Avoid spraying any insecticides when target plants or flowering plants likely to be hit by the spray are in bloom.

• A shallow source of water is also attractive to pollinators. A pot saucer partially filled with sand, then topped with water so that it just covers the sand works nicely. Add a few flat stones to give them a place to rest while they drink.

As far as recommending products that contain imidacloprid (Bayer Advanced Tree & Shrub Insect Control and other home gardener formulations), sometimes there is not an effective least-toxic pesticide to control a problem. Insects such as emerald ash borer and hemlock woolly adelgid are found on very large trees that home gardeners cannot spray without hiring a commercial applicator, but they can easily apply a systemic insecticide as a soil drench. Most least-toxic products require repeat applications and it may not be affordable to pay an applicator to spray that often. Also, insects such as emerald ash borer are best controlled with systemic insecticides (and a limited number of those!) since they feed inside host plants. I do not know of any least toxic products that provide adequate control of such insects. Finally, products that are applied as a soil drench are much safer for home gardeners to apply compared to spraying. Spraying creates an opportunity for the wind to carry the spray to non-target plants, and the person doing the spraying is much more likely to get the product on themselves in the process; that is much less likely when applying the product in a watering can.
Perhaps it seems reasonable to remove plants that require such treatments, and in some circumstances that would be the correct choice. However, people are attached to their trees. Many have sentimental value – those planted to commemorate life events or planted by ancestors – or simply add to the value of a landscape. When you lose a large tree, shade gardens are transformed to full sun gardens in an instant, with resulting loss of understory plants that cannot take so much sun.


Trees & Shrubs bees like:

Red Maple (Acer rubrum)

Butterfly Bush (Buddleia davidii)

Buttonbush (Cephalanthus occidentalis)

Redbud (Cercis canadensis)

Summersweet (Clethra alnifolia)

Hawthorn (Crataegus spp.)

Inkberry (Ilex glabra)

American Holly (Ilex opaca)

Apple (Malus spp.)

Crabapple (Malus spp.)

Flowering Crabapple

Black Gum (Nyssa sylvatica)

Sourwood (Oxydendrum arboreum)

Cherry (Prunus spp.)

Black Currant (Ribes)

Black Locust (Robinia pseudoacacia)

Blackberry, Raspberry  (Rubus spp.)

Linden (Tilia spp.)

Blueberry (Vaccinium spp.)

Arrowwood (Viburnum dentatum)

Annuals & Perennials bees like:

Anise hyssop (Agastache foeniculum)

Root Beer Hyssop (Agastache rupestris)

Ornamental Allium (Allium spp.)

Butterfly Weed (Asclepias spp.)

Aster (Aster spp.)

Borage (Borago officinalis)

Cosmos (Cosmos spp.)

Crocus (Crocus spp.)

Purple Coneflower (Echinacea purpurea)

Viper’s Bugloss (Echium vulgare)

Globe Thistle (Echinops ritro)

Joe-Pye Weed (Eupatorium spp.)

Fennel (Foeniculum vulgare)

Blanket Flower (Gaillardia grandiflora)

Snowdrops (Galanthus spp.)

Perennial Geranium (Geranium spp.)

Sunflower (Helianthus spp.)

Lavender (Lavandula spp.)

Shasta Daisy (Leucanthemum superbum)

Blazing Star (Liatris spp.)

Four O’clock (Mirabilis jalapa)

Mint (Mentha spp.)

Bee Balm (Monarda spp.)

Catmint (Nepeta spp.)

Basil (Ocimum basilicum)

Oregano (Origanum spp.)

Russian Sage (Perovskia atriplicifolia)

'Little Spires' Perovskia

Garden Phlox (Phlox paniculata – powdery mildew resistant varieties such as ‘David’)

Mountain Mint (Pycnanthemum incana)

Sage (Salvia spp., annual and perennial varieties)

Pincushion Flower (Scabiosa columbaria)

Goldenrod (Solidago spp.)

Germander (Teucrium spp.)

Thyme (Thymus spp.)

Verbena (Verbena spp.)

Ironweed (Vernonia spp.)

Zinnia (Zinnia spp.)

A portion of the Haagen-Dazs grant has been allotted to Penn State Master Gardener programs across the state for them to plant demonstration pollinator gardens. In Allegheny County, the pollinator gardens are part of our established demonstration gardens in North and South Parks and include many of the plants suggested above. Garden in the Parks Field Day will be held Saturday, August 14, 2010 from 9:00 am-1:00 pm. This free event includes tours of the gardens, programs on beekeeping, and garlic and tomato tasting. The North Park Demonstration Garden is located at the intersection of Babcock Boulevard and Wildwood Road at the Veterans' Monument. The South Park Demonstration Garden is located at the intersection of Corrigan Drive and McConkey Road. The South Park Wave Pool is on McConkey Road.



Beneficial insects

Spraying Pesticides


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