Let Your Bees Do the Gardening
If you’ve neverequated those big, juicy, homegrown tomatoes — or lack thereof — with bees, it’s time to grab some wood (literally). From alkali bees to shaggy fuzzy-foot bees, you’ll harvest bigger fruits and vegetables, as well as higher yields, if you have enough of these pollinating bees visiting your garden. By planting insect-pollinated plants and creating bee habitat, your garden bounty will ripen faster and taste better. I bet you’re thinking gardening is sounding a whole lot easier right about now.
Cornell University researchers have found that bee-assisted pollination of strawberries can increase fruit size up to 40 percent. Other crops that depend upon native bees for pollination include tomatoes, peppers, eggplants, pumpkins, squash, and melons, as well as most berries and fruit trees. Heavy reliance on pesticides, loss of habitat, and monoculture crop systems have decimated pollinator populations.
“Monoculture makes it impossible for any bee, native or otherwise, to keep year-round populations sufficient for pollination,” says David Green, who maintains the native bee website Pollinator. “A modern orchard has such a flush of bloom in spring that the pollination task is overwhelming. The rest of the year, it’s starvation or even a toxic environment.”
Image by Getty Images/magdasmith
Besides avoiding pesticides, you can support native bee populations by protecting natural areas on your property; leaving field and road borders unmowed to provide habitat for ground-nesting bees; and planting or preserving stands of native flowering plants (that the bees use for food) in pastures and hedgerows. A diverse selection of flowering plants and food crops ensures that pollinators have a steady supply of nectar and pollen throughout the growing season.
Take a close look at the flowers in your garden, and you’ll quickly see that honeybees, which are native to Europe, have plenty of company, including numerous native bee species with specialized talents. But while honeybees are commonly protected by a beekeeper, native bees have no human guardians. That’s why it’s important to help increase native bee populations in your own area.
Like honeybees, native bees feed on nectar while gathering pollen to take back to their nests as food for their young. In the process of gathering pollen, native bees pollinate flowers, often doing a better job than honeybees on certain crops, such as apples, berries, alfalfa, and almonds. For instance, pumpkin growers from Wisconsin to Alabama are recognizing the value of squash bees, a short-lived native species that often outnumbers honeybees visiting squash blossoms, even when honeybee hives are nearby. In areas where cool temperatures limit honeybee activity during the spring blooming of fruit trees, native mason bees do the job, because they’re better adapted to cool weather.
Image Getty Images/Julia Nikonova
Pollination in some crops is a collective effort among different species, however. Researchers at Ohio State University (OSU) found that 18 species of native bees were doing most of the pollinating work in nearby strawberry fields. These native bees don’t produce honey, and they can’t be reared in managed hives. But when they’re given even small patches of suitable habitat, such as a fencerow or diverse garden, some of the 4,000-plus species of native bees will show up.
“In a 20-acre woodland park that includes trees and flowers and hasn’t been sprayed with pesticides, there may be 100 species of native bees present on a summer day,” says Jim Cane, research entomologist at the U.S. Department of Agriculture’s Pollinating Insects Research Unit (Bee Lab) in Logan, Utah.
According to the National Sustainable Agriculture Information Service, the following native bees are particularly good pollinators of certain crops, although they pollinate other flowering plants as well:
- Alkali bees: onions, clover, mint, and celery
- Bumblebees: blueberries, tomatoes, eggplants, peppers, melons, raspberries, blackberries, strawberries, and cranberries
- Carpenter bees: passion fruit, blackberries, canola, corn, peppers, and beans
- Leafcutter bees: legumes (especially alfalfa) and carrots
- Mason bees: almonds, apples, cherries, pears, plums, and blueberries
- Shaggy fuzzy-foot bees: blueberries and apples
- Squash bees: squash, gourds, and pumpkins
It’s also important to understand that male bees can’t sting — a bee stinger is a modified egg-laying organ — and females won’t sting unless they’re provoked. “They have no honey to protect, so they’re not built to defend themselves from mammalian predators,” Cane says.
If you find that you like sharing the company of native bees, or you want to enlist their help to pollinate your plants, some species will accept human invitations in the form of nesting boxes.
The Secret Life of Bees
Big, fuzzy, black-and-yellow bumblebees and a few types of small sweat bees are the only native bees that live in colonies. Most other species live alone and associate with others only long enough to mate.
Image Getty Images/edsongrandisoli
Mason bees, carpenter bees, and leafcutter bees are called “cavity nesters” because they make their nests in the holes of trees, fence posts, firewood, hollow plant stems, or handmade bee-nesting blocks. More numerous ground-dwelling bees dig tubular burrows no larger than a drinking straw. Bumblebees often make their home in underground burrows vacated by rodents.
Like honeybees, bumblebees are general feeders that visit a broad range of host plants. But many wild bees have restrictive tastes and stick close to the plants they were born to serve. Squash bees, for example, followed early strains of squash as native people moved the crop northward from Central America. Females emerge in early summer and only fly in the morning when squash blossoms are open. In the afternoon, you can often find males curled up asleep in closed squash flowers (yes, bees do sleep).
Cane recently studied a specialist bee that only pollinates rabbiteye blueberries, and does so with amazing efficiency. The adult life of a specialist bee is quite short, but in only a few weeks, one often pollinates more plants than 100 honeybees. Because specialist bees need pollen from specific plants, they tend to stay close to home and forage in smaller plantings, says James Tew of OSU’s Bee Lab. Most native bees pose no problem for plants, though leafcutter bees do harvest rounded leaf pieces from roses, ash trees, and several other plants, which they use to build their nests. “The small amount of leaf material taken is a bargain when the pollination activities of leafcutter bees are considered,” Tew says.
Image Getty Images/kojihirano
Various species of the leafcutter bee have been found to be much better pollinators of alfalfa, blueberries, carrots, sunflowers, and onions than honeybees. For example, in an enclosed greenhouse where carrots were being grown for seed, researchers found that 150 leafcutter bees could do the work of 3,000 honeybees. One nonnative species, the alfalfa leafcutter bee, is now reared by the millions because it does such an outstanding job pollinating alfalfa grown for seed.
The Native Edge
Particular characteristics contribute to native bees’ pollination talents. Many native bees are quite hairy, and tufts of hair, such as those on the abdomens of female leafcutter bees, serve as soft brushes that gently transfer pollen from a flower’s stamens to its stigma. The buzz factor is also important because some flowers, such as blueberries and most members of the tomato family, need to be vibrated to shake the pollen loose from the stamens. Scientists call this process “sonication,” but University of Arizona entomologist Stephen Buchmann, co-author of The Forgotten Pollinators, came up with the phrase “buzz pollination.” Bumblebees, digger bees, and several other native bees are great buzz pollinators.
The diversity of native bees matches the diversity of native plants. With the help of his camera, David Gordon, a professor of entomology at Pittsburg State University in Kansas, has seen that some native bees have long tongues, so they can lap nectar from tubular flowers, while others have shorter tongues more suited to flat blossoms. Native bees also vary in size from 1/2-inch sweat bees to 1-inch carpenter bees.
A Garden to Call Home
Native bees seldom travel more than a quarter mile from their nests, so improving bee habitat can have a direct benefit in your garden. The Xerces Society, a nonprofit insect preservation group in Portland, Oregon, suggests ways to make your property bee-friendly:
- Minimize the use of pesticides, and avoid spraying botanical or biological insecticides in the morning, when native bees are most active.
- Grow a diverse selection of flowering plants, including as many native species as possible.
- Grow squash, sunflowers, blueberries, and strawberries every year to maintain resident populations of the specialist bees that serve them.
- Leave some areas of your yard or garden uncultivated so you don’t disturb bees that nest in the ground.
The same plants that attract butterflies and beneficial insects often attract native bees. Plants that have a long blooming period benefit these insects groups the most. For example, willows and redbuds that bloom in the early spring can be followed by fruit trees, brambles, and red clover before your summer vegetables and flowers take over as primary host plants. Then, keep the pollen flowing into fall by growing late-blooming asters and allowing goldenrod to flourish along fencerows.
Image Getty Images/Kondor83
With a solid food supply nailed down, you can further encourage native bees by providing attractive nesting sites. For ground-nesting bees, a patch of uncultivated, well-drained soil that gets morning sun will work well, as long as you avoid disturbing it with vehicles and tractors. You can also make a sand pile or sand pit, or simply fill a planter with sand and place it on a warm, south-facing slope.
If you see bumblebees buzzing around the roots of a tree, leave them alone; they’ve probably established a colony in a burrow vacated by mice or voles.
Improved pollination aside, good food and habitat for native bees have a ripple effect in the natural world. Native bees pollinate trees and wildflowers, which in turn provide food for wildlife. Cane says that because wild bees are vegetarians, they’ll never ruin your barbecue by buzzing around your burgers. “Sit down and enjoy the bees,” he says. “They’re great fun to watch.”
Barbara Pleasant is an expert in organic gardening, with more than 25 years of experience. She gardens in southwest Virginia, where she grows an abundance of bee-loving plants and provides a welcome habitat for wild bees.
Consider planting an herb or ornamental garden just for the bees. Install a hedge of boxwood around the edges to protect pollinators from wind. Bees prefer plants clustered together for added protection.
- Lavender (Lavandula spp.): An aromatherapy classic, this perennial is tough and drought-resistant once established.
- Basil (Ocimum basilicum): Tuck a few of these plants into your garden, and the bees will come. Use both green- and purple-leafed cultivars.
- Butterfly weed (Asclepias tuberosa): Draw in bees and butterflies with this trouble-free, hardy perennial’s bright-orange flowers.
- Thyme (Thymus vulgaris): This perennial ground cover is a favorite of bees. It comes in many forms and can naturalize.
- Feverfew (Tanacetum parthenium): Hardy and cheer-ful, this perennial has white, daisy-like flowers and grows 2 to 3 feet tall, with dwarf cultivars available as well.
- Sunflower (Helianthus annuus): A tall annual that’s perfect for the back of the garden, these flowers come in a wide variety of bright colors.
- Rosemary (Rosmarinus officinalis): This fragrant herb must be brought indoors for winter in colder climates.
- Oregano (Origanum spp.): These fragrant herbs are low-growing summer bloomers, and they’re almost as useful in the landscape as they are in the kitchen.
- St. John’s wort (Hypericum perforatum): This carefree, hardy perennial, with its golden-yellow flowers and dark-green leaves, blooms from late spring to early summer.
- Yarrow (Achillea spp.): Perennial and dependable, native yarrow’s flat flowers
are available in a variety of colors, including soft-yellow, red, and white.
- Russian sage (Perovskia atriplicifolia): The soft, blue-purple blossoms and finely cut silvery leaves of perennial Russian sage add a lovely, airy look to the garden. This hardy perennial plant is drought- and heat-tolerant, and a beautiful cover for larger, more substantial flowers.
- Anise hyssop (Agastache foeniculum): This licorice-scented perennial flowers in midsummer, attracting bees and other pollinators.
- Bee balm (Monarda spp.): Bees seek out the tubular flowers on this striking perennial plant.
- Black cohosh (Actaea racemosa): These tall, beautiful plants are, at times, covered by so many bumblebees that the white flowers that bloom in late spring and early summer seem to disappear.
- Borage (Borago officinalis): This annual herb is easy to grow and reseeds readily.
Bees love its bright-blue blooms in summer.
- Catmint (Nepeta racemosa): Honeybees love the spikes of this plant’s tiny purple flowers that bloom in late spring.
- Greek mullein (Verbascum olympicum): The tall flower stems of this perennial attract bees, and the plant readily reseeds.
- Purple coneflower (Echinacea purpurea): This perennial flower provides pollen for many honeybees and bumblebees.
— Kathleen Halloran and Jean English
Dos and Don’ts
Here are some tips for encouraging and protecting bees around your place:
- Handpick pests off plants, or spray with a soap-and-water solution
- Grow an assortment of flowering native plant species that have different colors and shapes
- Provide nesting spots
- Spray pesticides
- Destroy any hives; find a beekeeper to move them
- Grow a monoculture
— Karen K. Will