Enjoyment of these wonderful bees is only one of the reasons for having them in the garden. They are excellent pollinators of many fruits and vegetables including raspberries, cranberries, peppers, squash, blueberries, and strawberries and actually are better than honeybees at pollinating tomatoes and eggplants. An individual bumblebee can carry more pollen than an honeybee but honeybees live in colonies of 10,000-30,000 bees while bumblebee colonies have only 50-500 bees so overall honeybees are considered more effective pollinators.
Bumblebees are like their close relatives the honeybees in several ways. Both are social insects that live in a colony with one egg laying queen and many workers that are the daughters of the queen. During mating season drones are produced. Both kinds of bees produce honey but bumblebees have much less and do not have flat vertical combs. Bumblebees can get to work earlier in the morning than most insects because they can shiver their flight muscles to keep warm but they have a shorter life span because all but the queen die in the cold months. In the spring the queen goes alone in search of a new site and usually finds one in a clump of grass or in a cavity in the ground made by another animal. A mouse nest is a favorite.
I want to encourage bumblebee colonies in my garden and so I try to avoid disturbing areas that might have nests. I also grow plants that attract them and provide the nectar they need. They are especially fond of purple, blue, and yellow flowers; some species have long tongues and need flowers with long tubes of petals like clovers, vetches, and thistles. In spring, rhododendrons, azaleas, willow, and beardstongue (Penstemon spp) bloom, while in summer, Salvia farinacea ‘Victoria’, Anise hyssop (Agastache foeniculum), bee balm (Monarda fistulosa, Joe-pye weed (Eupatorium maculatum, aster, and goldenrod (Solidago spp) do so. The dahlias and zinnias in my garden provide resting spots for bumblebees in late afternoon and evening after a hard day’s work.