by UC Master Gardener Rebecca Jepsen
Reports of Africanized bees in Contra Costa County, which turned out to be ordinary European honeybees, has people thinking a lot about bees and their place in our gardens.
Bees are responsible for pollinating nearly 30 percent of all the food we eat. Their cross-pollination also is crucial for the survival of most of our native plants.
"The diversity and abundance of bees in your backyard varies greatly on the diversity of flowers available," says Robbin Thorp, entomology professor emeritus at UC Davis. "Help encourage bees into your backyard and garden with a variety that blooms all year long."
Thorp recommends growing lavenders, rosemary, salvias, ceanothus, ribes, lupines and California poppies. For pops of color add asters, sunflowers, cosmos, penstemon, cuphea and nepetas. Plant herbs that both you and your bees will enjoy such as parsley, chives, dill, basil, borage, mint and fennel.
Here are some of the more common bees you'll likely find in your yard.
Honeybees, which are ¾-inch and can vary in color from blonde to black, represent only a small fraction of the total bee population but they play a critical role in pollinating more than 40 varieties of fruit, nut, vegetable and seed crops valued at more than $1.5 billion per year.
Bumblebees are up to 1-inch long. They are more round, and are black or yellow with white or orange bands. Bumblebees are social and, although similar to honeybees, generally have much smaller colonies. They produce only enough honey to provide for themselves and are not used for commercial production.
Carpenter bees are shiny, black and as large as a bumblebee. They drill into wood, a trait that gives them their name, to create tunnels where they breed and raise their young. Although you might see carpenter bees drilling into the side of your home or other wood structure, they will seldom do significant damage. Make sure all surfaces and your siding are painted as they prefer untreated wood. However, if you suspect they are doing significant damage, you can treat the holes with insecticidal spray or dust. Wait two to three days, make sure the holes are empty, and then plug them with steel wool and caulking.
Leafcutter bees are small, smoke-colored bees with pale abdominal bands. They are productive pollinators, often doing 20 times more pollinating than honeybees. They are passive, solitary bees that need bare ground in order to nest and lay their eggs. For this reason, don't practice wall-to-wall mulching. Leave some bare spots for the bees.
While some may be upset by seeing a bee swarm, Elina Niño with the Honey Bee Research Facility at UC Davis, urges people to remain calm.
"If you see a swarm or nest of bees, don't panic," she says. "Just move away as quickly as you can and call your local extension office or beekeeping association. Don't swat or try to kill them; a dead bee can release an alarm pheromone that could mark you as a potential threat to other honey bees."