Utah Pests News Winter 2010

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Encouraging Native Pollinators in your Yard and Garden

 
  Figure 1.   Many species of sweat bees, such as the one shown here foraging on apple blossoms, are native to Utah.

For many people, honey bees immediately come to mind when considering pollination.  However, just about any animal that visits a flower in search of nectar is a potential pollinator.  This includes butterflies, moths, bats, hummingbirds, and native bees.  There are over 4,000 species of wild bees in the United States; 900 of these species are native to Utah (Figure 1).  With the exception of bumble bees and some sweat bees, native Utah bees are solitary, not social, like honey bees.  Female solitary bees each build their own nest, although often they nest in aggregations.

There are three things that you must consider if you would like native pollinators to thrive in your yard and garden:

  • Pollinators need continuous, high quality forage.
  • Pollinators have shelter and other habitat needs.
  • Pesticides can be harmful to pollinators.

To attract a wide variety of pollinators, you need a variety of flowering plants.  Try to plan for continuous bloom throughout the growing season.  Although it can be advantageous to plant native plants, non-natives can also be a good choice, if thoughtfully selected.  Water-wise plants make an excellent choice.  Different pollinators are attracted to different flower colors and shapes.  This can actually make planning the garden more fun, and the finished product more enjoyable.  It is important, however, that you do not introduce invasive plant species.  Keep in mind that some plants which are appropriate for gardens in some parts of the country can be invasive, bothersome weeds in other areas.

In addition to food, pollinators also have other requirements, such as shelter and nest materials.  Trees, bushes, and other vegetation can provide butterflies, moths, and hummingbirds with protected areas for perching, nesting, and hibernation.  Trees can also meet other habitat requirements; for example, hummingbirds often collect nest materials from willow trees.  Pollinators need both sun and shade.  Often they will bask in the sun early in the morning, and build their nests in shady spots.  And finally, pollinators need sources of clean water.

 
 
Figure 2 (top).  A log with holes drilled into it provides nest sites for solitary bees.  In this photo (top), the mud-covered holes are completed bee nests.

Figure 3 (bottom).  Empty reeds have been bundled together and placed in a plastic container to protect them from the rain.  Bees are actively nesting in many of the reeds.
 
The habitat needs of native bees are similar to the needs of other pollinators.  They need sunny areas, shady areas, shelter, and nest materials.  Native bees fall into two categories: those that nest in the ground and those that nest in cavities.  For those that nest in the ground, it is important to provide areas of open, well-drained, loosely packed soil.  They cannot nest in areas with weed barriers, thick mulch, thick turf, or small gravel.

Some of the easiest pollinators to actively encourage are bees that nest in pre-existing cavities.  There are several options available, depending on the level of time and effort you would like to invest.  If you have raspberries in your farm or yard, leave the canes pruned high rather than cutting them close to the ground.  Solitary bees can build nests inside these canes, as well as other pithy stems that you leave long, such as Siberian iris flower stems.  If you do not have plants in your yard with long, pithy stems, you can easily provide nest sites for bees by drilling holes in a log or stump (Figure 2).  If you are interested in actively managing cavity-nesting bees, you can provide bundles of hollow reeds or cardboard tubes, or construct nest blocks, and place them in a sheltered area (Figure 3).  Also, cavity-nesting bees often need other materials to complete their nests, such as mud, leaf pieces, or plant fibers.  Don’t be alarmed if you see bees collecting leaf pieces or plant fibers.  It is highly unlikely that they will collect enough to seriously damage the plant.

Pesticides can be harmful to all pollinators.  Even botanical insecticides can harm bees and other pollinators if not used carefully.  Seek other methods of controlling weeds, diseases, and insect pests before resorting to pesticides.  If you feel you have exhausted all other options, be considerate in your pesticide selection.  Use “softer” pesticides whenever possible.  Always read the label and follow directions carefully.  Treat only the affected areas.  Timing is important.  Some insecticides are only effective during a certain period of an insect’s life cycle. If you miss this period, you may affect your pollinators, but not effectively control your insect problem.  Also, always apply pesticides in the evening when bees are not active, and cover the nests with a tarp before spraying.

Once you realize how easy it is to encourage native pollinators to visit and live in your yard and garden, you will find that not only do they provide great pollination services, but they are entertaining and interesting.  More information on specific topics can be found by clicking on the following orange links:

garden plants that appeal to native bees
• more detailed information on native bees
NAPPC Pollinator Friendly Practices Guidelines 
pollinator conservation in agricultural settings
butterfly habitat
hummingbird habitat
• building stick nests  for solitary bees
building nest blocks  for solitary bees


More detailed instructions for managing blue orchard bees can be found at:

• the USDA-ARS Logan Bee Lab 
• “How to Manage the Blue Orchard Bee as an Orchard Pollinator


The Utah Native Plant Society  is a wonderful resource for more information on these and other pollinator-relevant topics.

-Cory Vorel, USU CAPS Coordinator