Native Plants for Bees

The bee you are picturing is probably not native

Honey bees are European, kept in managed hives, and effectively livestock. They are important agriculturally and they are not in ecological trouble in the way the headlines suggest.

North America has roughly four thousand native bee species. They are the ones worth planting for, and they behave nothing like a honey bee. Around seventy percent nest in bare ground rather than hives. Most of the rest nest in hollow stems, old beetle tunnels in wood, or snail shells. The great majority are solitary: one female builds a nest, provisions it, and dies, with no colony and no honey. Many are active for only a few weeks a year.

Specialists are the reason species choice matters

Most native bees are generalists that collect pollen from many plants. But roughly a quarter to a third are specialists, restricted to pollen from one plant genus or family, and they cannot substitute anything else.

There are bees that collect only from squashes, only from goldenrod, only from sunflowers, only from asters, only from evening primroses, only from Ceanothus, only from columbine. When the plant disappears from a landscape, the bee does too, whatever else is flowering nearby.

This is the strongest practical argument for planting natives specifically rather than any nectar-rich flower. A butterfly bush feeds adult butterflies and supports no specialist bee and no caterpillar. A goldenrod feeds dozens of species that have nowhere else to go.

Pollen matters as much as nectar

Nectar is fuel for the adult. Pollen is the protein that the larvae eat, and it is what a female bee spends her short life collecting.

Some heavily marketed garden flowers, particularly doubled cultivars, have had their pollen-bearing parts bred into extra petals and produce almost none. A double coneflower or a sterile mophead hydrangea can be visually spectacular and nutritionally empty. Single, open, unmodified flowers are the ones that carry pollen.

Habitat is half the problem

Planting flowers and leaving no nesting sites solves half a bee's needs.

Ground-nesting bees need patches of bare, undisturbed, well-drained soil. Not mulched, not landscape-fabric covered, not tilled. A sunny patch of open dirt at the edge of a bed is nesting habitat, and it is the thing most tidy gardens have eliminated entirely.

Stem-nesting bees need standing dead stems. Leave perennial stalks up through winter and cut them to about a foot in spring rather than to the ground, so the hollow ends stay available.

And skip the insecticides. There is no way to spray a garden for pests and keep its bees.

Sources: Xerces Society for Invertebrate Conservation (native bee ecology, specialist bee lists, and nesting habitat guidance); US Geological Survey Native Bee Inventory and Monitoring Lab (species diversity); Mt. Cuba Center (trials comparing cultivar and straight species pollen availability).