Extension Notebook: Grow successful native bee gardens

HILLSBORO, Ill. — Did you know that most Illinois native bees are solitary? This fact means that one female builds and provisions her own nest. These solo moms are doing the tasks that hive bees have provided for them by her offspring.

Selecting Sites for Solitary Bees

When planning for solitary bees, pay close attention to the plants that are available per season. Adults are active at different times or windows of time during the phenology of plants. Consider the type of soil as some solitary bees are attracted to a preferred soil condition for those that ground nest. Cavity nesting species use plant debris or wood to place their nests. Remember that pithy plant material such as woody stalks or perennial flower stalks are used as the brood cell partition, thus the need for stem stubble is necessary for the long linear cavity. Building materials are natural such as leaf pieces which leave circular patterns on leaves that help you to realize the presence of leaf cutter bees nearby. Finally, mason bees collect mud or chew on leaves to make a pulp to line brood cells and cap the nest.

Selecting Native Plants for Native Bees

The selection of native plants for bees is important for pollen and nectar. While selecting plants, consider the accessibility of the flower to the bee for these floral resources. Flower structure and size of the bee are important for compatibility; avoid double blooms on flowers that limit floral access and restrict pollination. Foraging trips have a purpose to find floral resources. Consider some pollinators as pollen specialists, only feeding on a limited number of plant genus or families.

If the location contains non-native plants, increase plant diversity with native plants. Remove invasive plants to restore native habitat. Avoid pesticide use in areas inhabited by native bees.

Beyond these, creating a connective corridor increases habitat and the number of species that can be supported. The more diversity in the design allows for connected spaces.

Garden Design Tips

Establish ground cover beneath established trees with a mixture of sedges, grasses, and perennials to create soft landings. Soft landings are diverse native plantings under keystone trees. These plantings provide critical shelter and habitat for one or more life cycle stages of moths, butterflies, and beneficial insects. An example of these practices is found at the Red Oak Rain Garden on the campus of University of Illinois at Urbana-Champaign.

To create a visually dynamic and interesting pollinator garden, plant in masses of plants with uniformity of color to improve foraging efficiency. This should lower the energy expenditure in finding the floral resources.

Learn more about various native plant selection, pollinators, and mapping garden spaces at the Illinois Pollinators website at https://illinoispollinators.org/.

Andrew Holsinger is a University of Illinois Extension horticulture educator serving Christian, Jersey, Macoupin and Montgomery counties.