Providing Habitat for Bumblebees: Gardening with A Big Buzz

Bees: The Cornerstone of Pollination

Bees are a cornerstone of nature's system for the pollination and reproduction of flowering plants. Without bees, many of the planet's important web-of-life food plants that feed animals and humans would not exist. Much needed attention has been focused on the plight of the honeybee and Colony Collapse Disorder. But there is also an urgent need to protect our bumblebees. Providing habitat-friendly gardens and landscapes are the most important thing gardeners can do to make a meaningful difference in helping to conserve and protect our native bumblebees and wild bee populations. By understanding their needs and planting to support them with food, we can help to undo what mankind has been inflicting on our wonderful insect friends.

Happy Faces and Bumblebees

For me, no other insect so readily brings a smile to my face than to watch a busy bumblebee buzzing around the garden. These slow flying, big fuzzy insects are a delight to have around us. These are the largest of our native bees and in many ways some of our most threatened. So it is very important that we educate ourselves, our neighbors and our communities' farmers and ranchers about how to work with the bumblebee to protect them from our activities like pesticide use, overgrazing and the destruction of nature areas resulting in the fragmentation of their habitats.

Important Pollinators

Bumblebees are very important pollinators of both wild native plants and agricultural crops. Because bumblebees have the ability to fly in cooler temperatures and when it is darker, they will be pollinating flowers earlier and later in the growing season and during the lower light of dawn and dusk. This ability is unique to bumblebees, as they are one of the few insects that are able to generate body heat (thermoregulation) and fly when it's cold, allowing them to live in more northern climates and at higher elevations.

What's for Dinner?

Bumblebees are generalists when it comes to choosing the flowers they pollinate while foraging for nectar and pollen. In general, they have a preference for blue, purple, pink, and yellow flowers and are actually color-blind to red (unless the red flowers have ultraviolet markers they can see).

Bumblebees, more so than other native bees and honeybees, prefer perennial plants as opposed to annuals, as perennials tend to have larger quantities of nectar. (See the list at the end of this article to learn the genera of perennial and woody plants that they prefer.)

Bumblebees are Social Creatures

Unlike most native bees, which are solitary, bumblebees are social insects that live in colonies. Unlike honeybee hives however, these colonies are much smaller and vary in numbers from 50 to 500 members. And they also differ significantly from honeybees in the lifespan of these colonies. Honeybees are perennial, with hives surviving the winter on stored honey and pollen. Bumblebees, however, are annual with the individual bees living one season, with only the queen bumblebee surviving through the winter. At the start of spring, she emerges from hibernation to begin foraging and looking for a suitable nesting site where she lays her eggs and re-establishes the colony.

Where's Home?

Providing undisturbed places for queen bumblebees to nest is a very important part of bumblebee stewardship. While there is much yet to be learned about the nesting requirements of different bumblebee species, we know that they can utilize both natural and man-made structures. Buildings, rock walls, abandoned underground burrows, under rock piles, cavities in dead trees, abandoned bird nests and bird nesting boxes are all utilized by the queen to establish and shelter her colony. This is why near-surface and subsurface disturbance of the ground by digging, tilling and plowing can be disastrous for bumblebees (and other native bees that also burrow in bare ground).

Don't Forget the Ornamental Grass

It is also known that native bunch grasses, such as Prairie Switchgrass (Panicum), Indiangrass (Sorghastrum), Dropseed Grass (Sporobolus), Little Bluestem (Schizachyrium), Big Bluestem (Andropogon), and Grama Grass (Bouteloua) provide nesting sites and protection for the queen to overwinter. (Remember how I'm always insisting that we leave our perennial plants and grasses standing over the winter?)

Go Natural and Organic

One of the biggest threats to bumblebees (and all bees) are the use of chemical pesticides, especially systemic neonicotinoids, widely sold at the "big box" stores and uninformed nurseries and garden centers. But often overlooked, is the use of agricultural chemicals on the soil such as diazinon (to "control" ground dwelling insects and their grubs), pre-emergent herbicides and fungicides. Unfortunately, these toxic chemicals are most commonly associated with lawn care and the lawn care industry. And these toxic compounds are being applied by the ton to the millions of acres of land covered by lawns. For so many reasons, if you have a lawn, care for it organically! (If you do need to protect your lawn from beetle grubs, the primary target of diazinon, use milky spore, a natural grub control. For above ground insects, diatomaceous earth is a safe, natural alternative control.)

The Xerces Society

As always when it come to insects, the Xerces Society is the go-to organization for good, scientifically based information on how the can protect our invertebrate (insect) friends. They have an outstanding book all about this incredibly wonderful group of pollinators titled Conserving bumblebees; Guidelines for Creating and Managing Habitat for America's Declining Pollinators. This is the most comprehensive book on bumblebees and indispensable for learning all about this wonderful group of insects.

Be Proactive and Plant Flowers

Currently it is thought that Franklin's bumblebee, native to southern OR and northern CA is extinct. And while once common, many other species are imperiled. Plant for bumblebees and help protect these incredible creatures. Because a world without bumblebees is a thought too sad to contemplate.

Bumblebee Attracting Old World Plants

Bumblebee Attracting Native Plants

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