Wild bee nests
Wild Bee Nests and Building Wild Bee Houses
Wild bees are important pollinators of many fruits and wild flowers. The best way to provide nests for native bees is to provide undisturbed areas where they can make their own nests. Some key elements to provide are standing, dead stems, downed logs, brush piles, and most importantly, undisturbed ground (both bare and covered with thatch).
Most bees (between 60 and 70%) dig burrows in the ground. These bees prefer dry, sandy soil bare of vegetation, often on hillsides. You can attract ground-nesting bees simply by making sure to leave some spots of exposed, undisturbed soil in your yard.
The other 30-40%, the cavity-nesting bees, require a bit more effort. These bees use hollow plant stems or holes in wood left by wood-boring beetles, instead of digging their own tunnel in the ground. A nesting bee will use mud, leaves, or another material to build walls and divide the tunnel into a linear series of small, sealed cells. Each cell contains a lump of pollen and an egg, which usually takes one year to develop into an adult bee and the cycle can begin anew. You can attract cavity-nesting bees by providing tunnels in a man-made structure called a bee house—like a bird house for bees. Three common types of bee house are stick bundles, wood blocks and observation blocks.If you would like to observe native bee nesting, you can construct your own nests for cavity nesting bees. Please note that these nests need maintenance otherwise they can cause more harm than good. Learn about wild bee diversity and how to attract them to your garden or farm by providing nesting habitat in this beautiful pamphlet written by Joel Gardner. Download free pamphlet (.pdf)
We suggest you create habitat for cavity-nesting bees by managing the stems in your garden.
Steps to create stem-nesting bee habitat
• Provide hollow and pithy stems from flowers and grasses.
• Cut stems in spring.
• Provide a variety of stem heights from 8 to 24+ inches.
• Provide a variety of stem diameters from 1/8 to 5/16 inch.
• Leave stems through summer, winter, and at least the first half of second summer.
• To deter parasites, don’t clump or bundle stems.
• Bees will use vertical, horizontal, or angled stems.
• Protect the plants from pesticide exposure.
• Provide diverse plants nearby to provide other nesting needs such as leaves, plant hairs, and resin.
• Provide open water for mud-building bees.
More information in this flier.
The Bee Real, Bee Everywhere project is an interdisciplinary collaboration between researcher Colleen Satyshur and artists Christine Baumler, Amanda Lovelee, and Julie Benda. Imagined as an experiment in providing places for bees to thrive in urban environments, four floating bee “skyrises” house removable cavity-nesting bee blocks. The blocks are arranged in the sculptures to create a comparison between East and South facing blocks and nest holes of different sizes.
Find out more about Bee Real, Bee Everywhere here.
Bumble bees are a bit different. The basics of what they need are a sheltered space with insulating material. In your yard, this can be a compost pile, piles of dried grass at the base of native grasses, or a raised bed that has sticks and logs at the base (look up hugelkultur to learn more). If you are able to leave leaves on the ground and add some logs to leave to rot, they seem to be attracted to those. Some people do make houses that bumble bees can use for nesting. People who put out houses have a 0-10% success rate so it may not be worth the effort compared to habitat creation. If you would like to try, the Bumble Bee Conservation Trust has created a guide: Making a bumble bee nest.