Scientists studied ‘lazy lawn mowers.’ It turns out they’re saving the bees, study finds

Sacrifices made for science: Researcher Susannah Lerman (pictured) and colleagues gave free lawn-mowing to those who participated in the study.
Sacrifices made for science: Researcher Susannah Lerman (pictured) and colleagues gave free lawn-mowing to those who participated in the study. U-Mass Amherst

Neighbors might not thank you if you cut back on mowing the lawn, but your local pollinators will.

Becoming a “lazy lawn mower” and trimming the grass every two weeks, rather than weekly, can help foster vital bee habitat in suburban yards, according to a new study from researchers at the University of Massachusetts Amherst.

More time between mowings means more lawn flowers (like clover and dandelions) have time to bloom in the yard, researchers said — and those blooming flowers can help improve struggling bee populations and increase biodiversity.

“Mowing less frequently is practical, economical and a timesaving alternative to replacing lawns or even planting pollinator gardens,” said Susannah Lerman, who authored the study and works as an ecologist at the University of Massachusetts Amherst and the U.S. Forest Service.

Lerman added that the findings provide a template for individual homeowners to take a small, individual step that could help the environment for everyone. “Sustainability begins at home,” she said.

Researchers asked 16 homeowners in Springfield, Mass., to use one of three mowing schedules during 2013 and 2014: Mowing once a week, mowing every other week or mowing once every three weeks. (An added perk of being in the study: The researchers offered to mow the participants’ lawns.)

Then the scientists waited to see how bees responded. It turned out that mowing every three weeks led to as much as 2.5 times more lawn flowers than in yards mowed more frequently, researchers said. But it was in the lawns mowed every two weeks that had the most bees, they found.

“I was amazed at the high level of bee diversity and abundance we documented in these lawns, and it speaks to the value of the untreated lawn to support wildlife,” Joan Milam, another University of Massachusetts researcher who worked on the study, said in a statement.

Worldwide, bee populations have been in decline in recent years, researchers said, as a result of ever-expanding cities, more and more farming and other loss of bee habitat. And that can have grave consequences given how important pollinators like bees are for supporting the environment and agriculture.

Colonies in North America and Europe in particular have been struck by colony collapse disorder — a little-understood phenomenon that happens when worker bees abruptly leave a hive, abandoning its queen and crippling it. Eventually, the disorder leads to a hive’s death, according to the U.S. Environmental Protection Agency.

Fewer hives were succumbing to colony collapse disorder in 2017 compared to previous years, according to the U.S. Department of Agriculture, but there are plenty of other challenges facing bee populations. That includes Varrora mites, which suck bees’ blood to survive and have been reported in more than 42 percent of commercial hives, Newsweek reports.

So what does the research mean for homeowners? The authors know that not every lawn in the country is exactly like the 16 they studied in Springfield, they said.

Still, “the findings may be applicable in all temperate areas where lawns dominate,” co-author Christofer Bang of Arizona State University said in a statement.

The study also points to the importance of allowing lawn flowers (that is, dandelions and clovers) to thrive, researchers said.

“There is evidence that even though lawns are maintained to look uniform, they may support diverse plant communities and floral resources if the owners refrain from using herbicides to kill ‘weeds’ such as dandelions and clover,” said co-author Alix Contosta of the University of New Hampshire.

The study was published in the May edition of the journal Biological Conservation. The researcher was funded through the National Science Foundation.