Why garden for Bumble Bees?
Bumblebees are a keystone species. This means much of our ecological system hinges on the survival of bumblebees. Not just native plants rely on these furry pollinators, but also many other organisms; over 250 insect species use bumblebee colonies for one or more of their life stages. We may not understand the contribution they make to our well-being but certainly without them we would notice big changes in plant and animal life.
All bee species are in decline around the world. Bumblebees are no exception. Research in Britain indicates that long-tongued bumblebees are at greater risk of extinction than shorter-tongued bumblebee species. It’s believed that the shorter-tongued types have greater access to a wider range of flowers than the more specialized long-tongued bumblebees. This may well be the case in Canada too.
In North America we have the additional problem of European bumblebee diseases having been accidentally introduced. This has caused a wide spread devastation in bumblebee numbers and population distribution. Too many species in Canada and the US that were once commonly found in busy backyards and quiet country lanes are now all but extinct, their numbers so few and far between that many have not been seen in over a decade.
Loss of forage and habitat, the common and casual use of pesticides, the rise in intensive agriculture, urban sprawl and climate change are all factors in pollinator decline and are leading causes in the disappearance of bumblebees.
We understand the importance of honeybees to our survival. There are a number of important food crops that rely on bumblebees for their ability to ‘buzz pollinate.’ Bumblebees need to keep a fairly high internal temperature to fly so they have the ability to disconnect their flight muscles from their wings while they are on a flower; they keep on buzzing to stay warm for flight. This is like joggers running in one spot while waiting for the traffic light to change. Tomatoes, peppers, and eggplants all use this buzz for cross-pollination. Our gentle buzzers are also better at pollinating blueberry and cranberry than honeybees for the same reason.
Thankfully it’s not at all difficult to garden with bumblebees in mind.
What Do Bumblebees Need?
Bumblebees, honeybees and the Blue Orchard mason bee all require lots of spring flowering plants. Having a garden early in flower is a big help to bees of all kinds.
For bumblebees, plant rhododendrons, heathers, violas, crocuses, runner beans, currants, and maples. Leave a few weedy plants behind; clovers, dandelions, and other early-to-bloom ‘weeds’ are ideal bee plants offering much needed pollen and nectar. Let’s not be too obsessed with being neat and tidy.
Different bumblebee species have different nesting needs, but luckily many are opportunistic, taking whatever is available. Some nest in abandoned mouse nests. Some in tussocks of grass on the ground and others in bird nests from last year or in disused birdhouses.
In the spring the only member of the colony alive is the fertilized queen. She has about two weeks to find a nest, start making wax, gathering pollen and nectar and to begin laying eggs. If she doesn’t find a suitable nest she’ll move into whatever she can find.
At this time of year we can place homemade nests in our gardens to attract and keep bumblebees in our gardens. Many of these nests are fun and simple to acquire or make. A few homemade nests give those new queens a greater chance of survival.
Among the simplest is an old teapot! Make sure inside the spout there isn’t a grid to keep tea leaves from flowing into teacups. If there is one, use a screwdriver and hammer to knock a hole large enough for a bumblebee queen to get in and out. Place a handful of some dry nesting material into the pot, dryer lint works well (finally a use for dryer lint!), and half bury the pot under a shrub in a sunny south facing spot in your garden.
Place some of that dryer lint into birdhouses in your garden for bumblebees. The birdhouses don’t have to be high off the ground—just a few feet up is enough, if that’s an issue in your garden. Again it’s important that it be placed in a south facing location with plenty of sun. If it’s placed high off the ground don’t worry about shrubs and what not. Focus on ensuring sunlight.
I always place bumblebee nests at the back of the border where they are out of the way. Frequently this isn’t much of a problem as only once out of every three years or so bumblebees occupy a homemade nest.
Once she has chosen her nesting site the young queen begins gathering pollen and nectar, making wax pots within which to store provisions, and laying eggs. When the eggs have developed into worker bumblebees, after about 14 days, they take over her outside duties. At this point the social life of the colony begins.
The queens are the super big furry and frequently colourful bees you see flying around in the early spring. If you see one flying without pollen on her legs she is still searching for a nesting site. The smaller, just as fuzzy and colourful bees, seen later in the spring and throughout the summer, are her daughters.
Later, as the summer draws to a close again, we see large fuzzy bumbles flying about. These are the virgin queens, the ones that will overwinter to emerge in early spring, starting out on their life’s journey.
These new queens need a north facing or shady location to hibernate in. They bury themselves in loose soil and wait for the spring. Frequently they can be found in friable soil, under mulch, and in compost piles. It might be a good idea to not turn your compost past late August to avoid disturbing sleeping queens. At least it makes a good excuse to put off that task until late next spring!
In many urban neighbourhoods a single backyard can be the overwintering site to many bumblebee queens. Often these are older homes with overgrown areas in the back that don’t see much light or foot traffic. Sadly these are also the homes that get bulldozed for development. When they are knocked down in the autumn, winter or early spring with all the soil and vegetation removed it isn’t just a bit of history gone for good, it’s also a whole generation of bumblebees gone from the community too.
Aside from placing nests in your garden to lend bumblebee queens a hand and ensuring your garden has plenty of spring blossoms, what other activities are there? Loads of interesting and exciting things can be done with bumblebees!
Have you ever petted a bumblebee? If you are very gentle and move slowly you can reach out and touch a bumblebee. If you listen closely you can hear her purring! Okay, that’s not true but you can definitely feel her buzzing, which is way better than a purr.
When was the last time you chased a bee? Why not try to follow a bumblebee home? On a lazy weekend afternoon with the kids in tow, wait to spot a bumblebee: If she has pollen on her legs, follow her as far as you can with your eyes and then run to the spot where you last saw her before she disappeared. Wait there for her to reappear. Is she carrying pollen still? Remember, she is bringing pollen home to feed the young larva. Pollen on her legs means she is still gathering or on her way back to the nest. When you see her without pollen she is on her way to find more food. Her nest will be in the direction from which she came. You’ll get the hang of it.
Why bother locating her nest? The more you understand about these bees the better off we’ll all be. A surprising amount is known about bumblebees and a surprising amount of very basic stuff is not known. Like where bumblebees nest, what plants they like to visit, and how far they travel from their nest to find food. Lots of stuff is not known and you can play a part in increasing our understanding of our local bees. Plus it is fun and helps us to see our neighbourhoods and communities differently.
An extremely rewarding activity is to plant a bumblebee garden. Here are a few ideas for what to plant. Remember to leave some undug soil in a north-facing or shady spot in your garden, to put out a few home made nests for bumbles and to let a few weeds be.
Some Flowers for Bumble Bees
• Runner beans
• Golden Rod