Pollinators are in peril.
Dire reports of colony collapse disorder, an umbrella term for steep population declines, have been making news for several years. Last month, the U.S. Department of Agriculture released a study finding that 31 percent of honeybee colonies died over the winter.
That's troubling for all of us, not just science and bee geeks, given that a third of the plants in our diet are pollinated by honeybees.
''It's not just a gardening issue, it's a food-safety issue," said Elizabeth Beckman, education coordinator for the Capitol Region Watershed District, headquartered in St. Paul, Minn.
Bee deaths are a complex problem, with multiple suspected causes, including disease, habitat loss, pesticides and climate change, said Elaine Evans, a bee scholar and doctoral candidate in entomology at the University of Minnesota.
But there's one simple thing that everyday people can do to help the bees: Plant habitat for foraging and nesting. Particularly native wildflowers. Ideally, in big clumps so bees can find them easily.
''Bees need abundant flowers, from April through September, and they need diversity," said Evans.
Bees also need undisturbed areas for nesting, Evans said. "They nest in the ground and need land that's untilled, that's left alone."
You might assume that what's growing in your garden is too inconsequential to make a difference. Evans disagrees.
She converted her own St. Paul boulevard to a "bee garden" -- filled with bee-friendly flowering plants, including bee balm, purple prairie clover, cup plant, New England aster and giant hyssop -- about five years ago. "Within a year, I saw tons more bees," she said, including the rusty-patched bumblebee, a once-common species that has suffered an especially steep decline and now is endangered.
The rusty-patched bees are "generalist pollinators that visit a wide variety of plants," said Evans, who's also a consultant for the nonprofit Xerces Society for Invertebrate Conservation, which has been tracking imperiled bumblebee species throughout North America. "They used to be one of the more common bees in the Twin Cities; then suddenly we weren't seeing them at all." In the past couple of years, there have been scattered sightings of rusty-patched bees, which Evans attributes, in part, to the increase in home gardeners adding plants that support them.
''Even a little bit of habitat like that can make a difference," Evans said. "Animals respond. They need it. They're pretty good at finding things."
While bees are good at finding bee-friendly plants, gardeners sometimes need a little help.
''A complaint we get a lot is 'Where do we get these plants?'" said Beckman. "You can get a plant called little bluestem at the garden center, but it might be from Kansas. It's not bad to plant, but you don't get the full benefit of a plant that's adapted to these growing conditions."
Truly native plants establish quickly, with deep roots that require little watering, and help protect the water quality of lakes and rivers by preventing runoff, Beckman said.
They also produce nectar that is especially attractive to pollinators, while cultivated plants that might have been bred for other traits, such as more flowers or a particular color, are less beneficial to bees.
''Even native species can be cultivated and hybridized to the point that they don't provide as much food," Beckman said.
Plants bought at a garden center also carry the potential of having been exposed to pesticides, including systemic neonicotinoids, which are especially insidious, according to Evans.
''They get into the tissue of the plant, and it ends up in the pollen and nectar." People buy pesticide-laced plants and take them home, without realizing they're introducing something that will kill, not nourish, bees. "You have to be aware of where your plants are coming from and how they were treated," Evans said.
And don't be concerned that a bee-friendly landscape will make you unpopular in your neighborhood. There's no reason a native-plant garden needs to look shaggy or unkempt, even compared with the manicured lawns around it.
''The fact is, native plants come in varying heights," said Beckman. "There are low-growing grasses. There are mounded plants. You can still have a neat, planned look."
If want to go "wild and woolly," your neighbors are likely to be much more accepting than they were a decade ago.
''I've been doing this work for 12 years, and the aesthetic has changed," Beckman said. "There used to be more emphasis on a highly groomed lawn, but now people are more amenable to a natural look."
When she moved to Minneapolis, she was the first in her neighborhood to plant the boulevard, she said. But since then, her neighbors on either side have followed suit. "You can see the influence growing."