Sunflowers and Wild Bees

sunflowerkathyFor several years I’ve tried to lure wild bees into my garden by providing food and habitat. Scientists believe populations of our native wild bees to be in decline. Single-crop farming has contributed to wiping out their habitat. And while many gardeners, including me, have worried about the plight of honeybees, wild bees suffer in silence. Their disappearance barely is noticed by any but a handful of entomologists.

Now there is a renewed effort to study their demise. News report from a study in the journal Science indicate that pollination by wild bees is more important than previously understood. And there is an awareness that losing wild bees may mean the loss of valuable pollinators essential for both native plants and food crops. Here is where sunflowers come to the rescue.

I grow native flowering plants for pollen, native grasses for habitat. I never use insecticides or herbicides and my garden has some luscious blooms from spring to fall. A few wild bees arrive and possibly nest. But not many.

Everything changed the year I planted a forest of sunflowers, Helianthus annuus, but only sunflowers that manufacture pollen. Sunflowers planted for seeds fall into this category. The many new decorative pollenless sunflowers are of no help because wild bees evolved to harvest sunflower pollen. That relationship goes far back in time.

Sunflowers are native to North America and once covered our wild lands and especially the prairie Midwest—the very place where massive farming has led to vast single crops. However, there’s a sunflower for nearly every state. More than a century ago, sunflowers left our shores and set up shop in places around the globe, supplying oil and seeds for humans, silage for animals. They supplied pollen and nectar for insects as well.

Once my forest of sunflowers bloomed I noticed more wild bees than I could count--far more than I could identify. And they appeared to get along with each other. Often one large bloom could accommodate five varieties of wild bees—some with velvety bodies, plump noisy bumblebees and tiny nearly transparent bees—all intent on their busyness of collecting pollen. Most wild bees are solitary and don’t build the gigantic hives of honeybees; many live in underground bungalows.

Rarely do they sting. And some don’t possess stingers that can penetrate human flesh. Our typical garden stingers are wasps. This mix-up results in homeowners killing harmless bees rather than targeting wasps as the true bullies. Since most wasps feed on other insects or decomposing organic matter, you can buy wasp traps that will attract only wasps and not bees.

By the end of summer, my vegetable and fruit gardens were amply pollinated. I saved many of the seeds of the sunflowers to plant the next summer. As sunflowers are bee pollinated, they may cross and not come true to the original sunflower. But you can always buy more of the cultivar you like and plant it alongside your saved seeds as a science experiment. The bees will love both.

There is one caveat: birds and squirrels will love the ripening seeds, too. I attracted as many goldfinches as bees when the seed heads began to form. They were welcome to the seeds. But when squirrels jumped on the stalks and tore apart the forming seeds I had to take action. I covered many of the seed heads with paper bags held onto the stalks with twist ties or rubber bands. Occasionally the squirrels would tear through the paper but I was able to harvest plenty of seeds for the next spring.

Plant sunflower seeds directly into the soil after the danger of frost has passed. They won’t transplant well from a pot because of a fragile taproot. Usually gardeners plant the seeds about two to three inches deep. They’ll emerge within five to 10 days and grow quickly. Water regularly when they are growing fast. Once they reach their mature height they are somewhat drought tolerant. If they need water they will let you know by wilting dramatically.

Large mammoth sunflowers create a magical garden for children. And because sunflowers face east, as to greet the sun, they appear otherworldly. Best of all, you may be creating a haven for some of nature’s most valuable and unsung heroes in the natural world.