Homeowners who replace traditional lawns with wildflowers, clovers and native grasses in an effort to slow the collapse of state's bee population could soon get assistance from the state of Minnesota.

Under a bill introduced by Rep. Kelly Morrison, DFL-Deephaven, the state would set aside $2 million over the next three years to help pay for lawn conversions by interested homeowners, schools and cities. The plan could help replenish food sources for pollinators of all kinds but will specifically aim at saving the rusty patched bumblebee, a fat and fuzzy species on the brink of extinction that seems to be making its final stand in the cityscapes and suburban areas of the Twin Cities, Milwaukee and Chicago.

The program would cover up to 75 percent of the cost of each project, and more for conversion in areas with a "high potential" to support the struggling rusty patched bees.

"When you look at [conventional] lawns, they're just food deserts for pollinators; there's nothing there for them at all," said Dan Cariveau, a professor at the University of Minnesota. "It could be a relatively cheap way to revive these food resources."

The state has run similar programs for farmers in rural areas for years, but this would mark the first effort to bring the subsidies to individual homeowners and, importantly, to cities and suburbs where many types of bees are surviving.

"We don't think of urban and suburban areas as being friendly to pollinators, but research is showing they play a pretty key role," Morrison said. "If we can be purposeful about the type of plants we're putting into lawn areas, we can really make an impact on helping pollinators come back."

While much of the public's affection goes to honeybees, for their produce, and Monarch butterflies, for their beauty and awe-inspiring migrations, research at the U has shown that bumblebees are particularly important to the Upper Midwest. They land on flowering stems and vibrate at a frequency close to a musical C note, which unlocks pollen other insects can't reach, and essentially dump it onto their bodies. The furry bees are especially good at collecting that pollen once it's released.

Rusty patched bumblebees once lumbered across grasslands and prairies throughout the Midwest, Ontario and New England. But over just the past 20 years their population has been decimated, dropping by nearly 90 percent, by U.S. Fish and Wildlife Service (FWS) estimates. The bees are left in only one-tenth of 1 percent of their historical range.

They've been threatened by many of the same reasons that most pollinator populations have fallen off a cliff — the Midwest's switch to more intensive and single-crop farming, powerful new pesticides, loss of food, a warmer climate and diseases that are made worse by the other four causes, according to the FWS.

Lately, rusty patched bees are rarely, if ever, spotted in places other than major cities in Minnesota, Illinois and Wisconsin. Cariveau said it's hard to say if that's because there are more people in cities to spot them or because the urban centers are providing some kind of refuge or food sources that farmlands aren't.

It is clear that neighborhoods have become critical habitat for them and many other types of bees; reintroducing natural flowers and clovers could be "fantastic," Cariveau said.

Some of the best sources of food, such as white clover, can grow and be mowed along with grass if people want to keep their yards usable, Cariveau said.

FWS has published a plant guide listing the best foods for rusty patched bees.

A companion bill in the Senate was filed by Republican Jim Abeler of Anoka, giving pollinator advocates hope that the program will have bipartisan support.

The lawn subsidy was one of the most widely supported recommendations to come out of a pollinator task force set up by former Gov. Mark Dayton, which was made up of environmental advocates, scientists, farmers, food processors and other stakeholders.

"I think we could all see there is a need to feed bees all across the state," said Erin Rupp, founder and executive director of Pollinate Minnesota.

Greg Stanley • 612-673-4882