By Alan Harman, Michigan – For thousands of years, bees have been helping feed people, but now in the face of an onslaught of chemicals and disease, they’re in need of a helping hand. One course of action you can take is growing plants that attract bees.
Both wild and managed bee populations have been in decline for the last 25 years, but since 2007 the loss of bees has accelerated dramatically as a result of Colony Collapse Disorder. It’s a mysterious malady that sees the bees simply fly from their hives never to return.
Beekeepers are investing a lot of time and money seeking a solution to the bee population decline, but in the meantime, gardeners can be the frontline troops in the fight to save not just honeybees, but all of nature’s pollinators. All they need to do is create a bee garden.
“Now more than ever, it is critical to consider practices that will benefit pollinators by providing habitats free of pesticides, full of nectar and pollen resources, and with ample potential nesting resources,” Rufus Isaacs and Julianna Tuell of Michigan State University’s (MSU) Department of Entomology say in a briefing paper.
A gardener can attract a diverse array of other wildlife, including butterflies and hummingbirds.
There are about 3,500 species of native bees in the United States, and plants that attract bees changes with the regions and the season.
Gardeners can color-code their properties, as bees are especially plants that attract bees are typically blue, purple, orange and yellow flowers, particularly those with short tubes or no tubes. Long-tongued bumblebees prefer flowers with deep corollas and hidden nectar spurs, while hummingbird-pollinated flowers are more likely to have red flowers with deep tubes, experts say.
Plants that attract bees need to be in full sunlight and in groups. Bees often overlook flowers grown in shade as well as those grown singly or in twos or threes.
Plants that attract bees should be close to water, such as a birdbath, fountain or farm pond design, not only to lure bees but also to sustain them. Barrels of water that trickle out onto pebbles can be an attractive feature bees will use.
Bees especially need water in areas such as the Southwest where temperatures can get so high the honeycomb can melt in the hive.
“You need a supply of water so bees can bring it back and distribute it around in the hive, retired MSU entomology professor George Ayers says. “They then form groups and fan their wings to evaporate the water and cool the hive. The question to ask is if you don’t provide a good clean supply of water, where might they (get) it from?”
Professor Gordon Frankie of the University of California at Berkeley’s College of Natural Resources, says in a report published on the university’s website, there are many factors that make a garden attractive to bees other than the flowers it contains.
“Simple things like the layout and light exposure of your garden can have a huge effect on the number and variety of bees it attracts,” he writes.
One of these actions is to leave bare soil for ground-nesting bees to dig small tunnels where they lay their eggs and rear their young. Frankie says the increasing use of garden mulch, promoted as an “eco-friendly” method for suppressing weeds and conserving water, has made life harder for ground-nesting bees.
“Leave some ground that is not actively being worked,” he says. Ayers says bee gardens are important as honeybees try to survive the onslaught of bee-killing Varroa destructor mites.
“I used to go around to botanic gardens and arboreta and see the plants the bees really like,” he says. “Since the advent of the mites that isn’t really possible any longer.”
Ayers, who has had a 60-year interest in entomology, says the secret of a successful bee garden is to plan a variety of plants that attract bees that bloom from early spring through summer into the fall.
He is America’s foremost authority after spending almost a quarter of a century researching bee-friendly flora. While his work is primarily aimed at beekeepers, it also has contemporary applications for country gardeners with an interest in plants that attract bees.
Ayers’s original concept was what he called diversionary plantings, a plan to lure bees away from the danger of fields and crops treated with pesticides.
“We’d plant something that would be super attractive and lure the bees out of the area where they don’t belong,” he says. “We screened a bunch of plants, some 57 of them, and chose plants out of that. But the beekeepers went ‘ho hum’. They weren’t interested—too much work.”
At his home in rural DeWitt, just outside Lansing, the state capital, Ayers uses his own garden to experiment by planting a variety of shrubs, trees, and herbaceous plants.
As a result, he has eight to 10 species of basswoods (Tilia spp), probably one of the finest collections in Michigan. “You can put together from species around the world a collection of basswoods that will bloom from about the middle of June (at least in Michigan) and into September.”
The trees are also known as Lindens or Limes, and apiarists call them honey or bee-trees. The seeds and twigs are eaten by wildlife. “Some are very floriferous,” Ayers says.
He also points to a shrub from Asia, sevenson flower (Heptacodium miconioides), and says it is a must in any bee garden. “It blooms in the early fall when not much else is blooming and the bees just love it,” he says. “When the calyx opens up, the sepals continue to grow after it blooms and turn red. They persist long past the flowering. It is a very attractive tree.”
Ayers grows the native Michigan holly bushes (Ilex verticilata) along a wetland at the edge of his property. It blooms in the summer, attracting the bees. “If you cover the flowers up with a net, they drip nectar,” he says. “They can be put into places you can’t do much else with. They are not beautiful, but they do really well along a marsh. In the winter they are quite handsome with their many red berries.”
Summersweet (Clethra altinafolia) also enjoys moist soil. It’s a native plant with white flowers and there are pink cultivars as well. “You come out in the evening when it is blooming and the air is just overwhelming with bloom,” Ayers says. “It is quite attractive to bees.”
Chinese chastetree (Vitex negundo variety heterophylla) is a famed plant that attracts bees. It puts out purple flowers. “I like this plant,” he says. “It has a wonderful reputation farther south.”
To introduce the Chinese chastetree to his garden, Ayers obtained seeds from a variety of places, thinking he would select the ones with the best flowers. Almost all of them died in the winter, but he saved the seeds of the survivors and planted them. His bushes now are the third or fourth generation of seeds that survived Michigan’s fierce winters.
“One of the things I think is really neat about this plant is it puts out clusters of seeds that the birds like in the winter. Cardinals seem to like it a lot.”
Growing blackberries and raspberries means growing additional plants that attract bees, Ayers says.
“You can also go out and pick and sell them at the farmers market.”
On a similar commercial basis, he likes American holly (Ilex opaca), or in places warmer than Michigan, European holly (Ilex aquifolium), which produces vast amounts of nectar. “Both have holly-like leaves and are not deciduous,” Ayers says. “If pests (both insect and fungal) are controlled so it doesn’t get holes in it, gardeners could make some money on the foliage at Christmas. But you are really going to have to know how to raise it because it is slow growing.”
Buttonbush (Cephalanthus occidentalis) is another important plant. “It seems to maintain itself pretty well and can grow with its feet in water,” Ayers says. “About July, it develops a flower that is spherical, about the size of a golf ball. It attracts butterflies and bees. I think I have seen 10 species of butterfly on it.”
Alsike clover (Trfolium hybridum), available from specialty growers and rural seed suppliers, also can be grown in damp areas. “It’s more dependable than white clover and bees do like it.”
Ayers has a tulip tree (Liriodendron tulipifera) that attracts bees but says his property is the northern border of where they can be grown.
“Sometimes when the species is in full bloom and it’s windy, the nectar drops like rain under the tree,” he says. “You could sweeten your cereal with a couple of these flowers it produces so much nectar.”
Hummingbirds like this tree, too.
Ayers came across the tropical import Diospyros lycioides, often called Karroo Bluebush, Monkey Plum or Red Star Apple, in Arizona when he was visiting the Tucson Botanic Gardens. “The flowers are not very conspicuous,” he says. “I thought there must have been a swarm of bees around until I saw they were working this plant. If I lived in the Southwest and wanted a bee forage plant, I would have that in my garden.”
Ayers says the bee-bee tree (Tetradium daniellii or Evodia daniellii in the older literature), an import from Asia, buzzes with bees. Lansing is the northern edge of where it can be grown. The tree grows 15-30 feet with some reaching 50 feet and blooms from mid-July well into August. It bears tremendous numbers of blossoms that attract bees at a time when other nectar supplies are drying up.
Anise hyssop (Agastache foeniculum) is a perennial that produces very well, but some areas attract only bumblebees and in other areas only honeybees. It smells like licorice and produces flowers around July. “It’s a nice plant to put in a bee garden,” Ayers says.
Among more commonly known plants, catnip (Nepeta cataria) provides good bee forage and growers can sell it at farmers markets to cat owners. Thyme (Thymus sp) is an-other bee garden entry that flowers heavily.
Milkweed plants (Asclepias sp. Linnaeus) are good bee and butterfly plants, most often associated with the magnificent monarch butterflies.
“The milkweed puts out its pollen in sort of a wishbone configuration,” Ayers says. “Down at the end of the wishbone in both arms are little bags of pollen and the bees, when they are working, get it caught on their legs and fly off with the stuff hanging on them.
“Sometimes they can’t get it pulled out of the flower and they die there. Some beekeepers don’t like it, but I think the general opinion is milkweeds are plants that attract bees, and are good for honey production.”
Of all the herbaceous plants he has tested, Ayers says native mountain mint (Pycnanthemum verticilatum) George Ayers checks out an experimental rapeseed field planted by Russell Freed at the Michigan State University agronomy farm.is probably the best in terms of enticing bees. It blooms mid- to late-summer.
Alfalfa is also a good plant that attracts bees, while cactuses fit in a bee garden for those living in the Southwest.
Lavender (Lavandula angustifolia or its older name Lavandula officinalis) has a great reputation in parts of the world as a bee plant and produces a fine quality, honey. California Poppy (Eschscholzia California), found in the western U.S. and northwestern Mexico, has a good reputation as a pollen plant but produces no nectar. Rosemary (Rosmarinus officinalis) is also a good honey plant.
Ball clover (Trifolium nigrescens) is a southern plant that’s very attractive to bees. “If I lived in the South, I would have a bit of this stuff around,” Ayers says.
Wingstem (Verbesina alternifolia) has been called the golden honey plant because this native blooms in the fall when bees are still active and looking for pollen and nectar. It produces a good fall honey flow and is particularly fond of wet areas. “If somebody wants it, they should be very careful where they plant it,” Ayers says. “It spreads to other people’s property.”
Some plants are good bee forages, but not recommended for obvious reasons. These include poison ivy and allergy-producing ragweed.
Entomologists say gardeners should avoid plants horticulturalists call “doubles.” They are bred to develop extra petals to replace the anthers. As a result, they produce little or no pollen or nectar and bees will not be attracted.
Ayers recommends old-fashioned roses with a single petal. “At the Arnold Arboretum in Boston they have a lot of old-fashioned roses, and the rose garden is one of the most attractive locations for bees,” he says.
One plus with a bee garden is you don’t have to be a purist about what you cultivate. Gardeners who want bees and butterflies can leave the weeds to prosper.
Ayers says the weed motherwort (Leonorus cardiaca) is a good bee forage as are dandelions. Motherwort protects itself with a lot of small spines and livestock owners don’t like it because it causes their animals problems when they eat it.
“Dandelions are very important for the spring build up,” he says. “The only people in the world that like dandelions are beekeepers. They love them because this stimulates bees to start making brood early in the year. So when the honey season comes along they have a lot of gatherers to go out and get it.”
Frankie agrees if the aim is to attract ample numbers of bees to improve the health of your garden, it’s worth considering leaving the weeds long enough to be useful in attracting helpful bees. “There is always plenty of time to remove these weeds once their flowers are spent, but before they’ve gone to seed.”
But watch out for the beautiful but obnoxious purple loosestrife (Lythrum salicaria), a good honey plant that is an introduced species that chokes out native faunas. “I wouldn’t suggest anybody plant this because you would have neighbors who hate you,” Ayers says.
In California, several native plants have pollen or nectar poisonous to non-native honeybees. Frankie says these include corn lilies, death camas, locoweeds and California buckeye. Widely distributed west of the Sierra, the buckeye is often planted as an ornamental for its good looks, fragrant flowers, and bold winter branch architecture.
However, Frankie says the use of most native or exotic plants can be one of the most critical factors when planning a bee garden. “Even if your priority is to have a native garden, it can be highly advantageous to include just a couple exotic plants on the basis of their bee-attractiveness. The bees will help your natives to thrive.”
But setting up a garden with bee plants is only half the job, no matter where you live. “All bees require places to hide from predators, to locate and court a mate or establish their nests,” he says. “Thus, they need you to help provide safe havens from predators, parasites, and chemical insecticides.
If the use of insecticides can’t be avoided, bee gardeners should try to use less-persistent products proven safer for bees and other pollinators. They should be applied after dark, when pollinators are safe within their nests.
Frankie also says making bee houses for the solitary native bees is easy. Simply take some scrap lumber and drill various sized holes three to five inches deep but not all the way through. Nail these securely in protected places under building eaves in the early spring.
You can also bundle paper or plastic soda straws and glue them to the bottom of paper milk cartons or coffee cans. Place them in protected shady, dry places in the early spring and the bees will come.
“If you have access to elderberry stems, cut and dry some into one-to-two foot lengths,” Frankie writes. “Different sized starter holes can be drilled into one end and into the sides of the woody stems.
“Sharpen one end like a tent stake and push them into the ground around your yard. The bees will soon find them.”
For a first-hand look at a bee garden, Ohio State University established its concept in 1994 that’s open daily to the public between dawn and dusk. Maintained by the university’s honeybee lab and the Tri-County Beekeepers’ Association, the 4,000-square-foot garden has about 80 species of plants.
All were selected for their attractiveness to honeybees and other pollinating insects, as well as for their appeal as garden plants. The garden is located next to the honeybee lab on the OSU Wooster campus.
The University of Minnesota’s plantinfo.umn.edu website is a great place for finding sources of plants and literature about them.
You don’t have to be an expert to design a bee garden. Many bee-friendly plants are familiar to casual gardeners.
Commonly named perennials include black-eyed Susan, Shasta daisies, yarrow, bee balm, cosmos, violets, Siberian Iris, sunflowers, sedum, asters, Jupiter’s beard, blue hyacinth, holly, trumpet vine and various clovers. Among annuals, marigolds, cosmos, hollyhocks, foxglove and geraniums are good choices.
Experts say gardens with 10 or more species attract the greatest number of bees. Large patches of like flowers should be planted close together to be most effective.
Which plants that attract bees will you be growing this season?
Originally published in Countryside May/June 2010 and regularly vetted for accuracy.