Kate Frey and Gretchen LeBuhn in “The Bee-Friendly Garden” consider all the various types of native bees found in northern California and how to create an inviting environment for them. There is a chapter on recommended bee-friendly plants, both woody and herbaceous, always with an emphasis on natives. There are lists of plants to avoid, including those with double flowers as single, pollen rich flowers have more to offer to pollinators. Thinking from the bee’s perspective, you are advised to plant more than single specimens, otherwise they “…may not have enough floral rewards to make it worthwhile.”
Providing sufficient nesting options is critical. While the authors briefly cover human-made nests and bee “hotels”, they encourage a more passive approach such as using plants that have naturally hollow stems and leaving a few logs around. They recommend leaving some bare patches of ground, free of layers of mulch that are troublesome for bees to dig through. Of course, like all wildlife, your bees need to have a pesticide-free environment.
Excerpted from the Winter 2017 Arboretum Bulletin.