Native Solitary Bees: Don’t Make Your Landscape Too Tidy This Fall

ground nesting bee on leaves

Cellophane Bee (Colletes thoracicus) is a solitary bee and valuable pollinator that nests in the ground. Photo by Hadel Go

Cooler evening temperatures might have you switching gears from planting and maintaining your landscape to fall decorating and garden cleanup chores. While cleaning up diseased and pest-infested plants in your yard and garden are important to prevent problems in the future, consider leaving healthy plants that could add visual interest this winter and provide nesting sites for many beneficial critters.

With more than 400 species of native bees in Maryland, these amazing little pollinators are a wonderful addition to your landscape. They are small and not aggressive. Some are specialists, which means they must have certain plants to feed on, while others are generalists and will visit a wide variety of plants. For amazing photos of native bees, check out the USGS Bee Monitoring Lab on Flickr.

As with all members of the animal kingdom, pollinators need food, water, and shelter in order to support life. Successful pollinator habitats include diverse flowering plants, food resources, and safe spaces for creating nests. As you begin cleaning up your yard and garden this fall, remember that these solitary bee species and many other beneficial critters rely on dead plant stems, fallen leaves, and other items that are often traditionally removed from the landscape.

dead plant stalks with new growth emerging at the base

Leave perennial plant stalks standing for the winter. Photo: C. Carignan

According to Colorado State University’s factsheet, Attracting Native Bees to Your Landscape, 90% of native bee species found around the world are solitary. Approximately 70% nest underground in the soil and about 30% nest inside hollow stems of plants and in tunnels left by other insects. Solitary female bees are responsible for collecting food, usually pollen, to include with each egg that she lays throughout the spring and summer. These eggs hatch into larva that spend the winter as pupa, which then turn into adults the following spring. Adult females die with the first fall frost. So in order to continue their life cycle, it is very important that their nesting sites are not destroyed in the fall.

To create friendly bee nesting habitats, provide dead wood like tree stumps or firewood for wood boring bees, plants with hollow stems (brambles and other perennials) for bees that need a tunnel-like structure, and areas of full sun, bare (un-mulched) soil, which ground nesting bees use for their nests.  Landscape fabric prevents ground-nesting bee’s ability to tunnel into the soil.

bee nesting box

Bee nesting box. Photo: Pixabay

Bee houses have gotten some attention in recent years and there are mixed messages about adding bee housing structures. Some evidence suggests that if not properly maintained, these well-intended additions could actually create a negative effect on populations. The houses provide a nice nesting area that results in large numbers of larva/pupa congregated close together, which could be easily targeted by predators, diseases, or parasites. For guidance on bee house maintenance check out this great factsheet from the Xerces Society.

Remember our unseen friends this fall and leave some of your plant materials in place to provide nesting and sheltering sites. Sit back, relax, and delay some of those cleanup chores until spring!

By Ashley Bodkins, Senior Agent Associate and Master Gardener Coordinator, Garrett County, Maryland, edited by Christa Carignan, Coordinator, Home & Garden Information Center, University of Maryland Extension. See more posts by Ashley and Christa.

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