It’s a simple idea: Stop mowing your lawn in the month of May to let flowers in the lawn, such as dandelions and clover, grow and support bees and other pollinators.

“No Mow May” was started in 2019 by Plantlife, a conservation charity based in the United Kingdom, in response to a well-documented loss of meadows and an alarming decline of native plants and animals there. Since then, it has been taken up by many gardeners and conservation advocates in North America.

Studies have shown that many flowers that grow in unmown British lawns do support British pollinators. But North America has vastly different ecological communities, composed of unique flora and fauna.

If you are interested in supporting pollinators, it is important to consider the ecological context of your yard – and #NoMowMay may not be an effective strategy. As entomology researchers who run programs on pollinators, we see better ways for people in North America to help pollinators flourish in their yards.

Most common lawn flowers in North America are not native to this continent but were brought here from Europe and Asia. Many, such as bull thistle, are noxious weeds that can displace native plants and contribute to problems such as soil erosion. Others, such as ground ivy, are aggressive, invasive weeds in natural areas.

Allowing these weeds to grow can increase their numbers in the landscape and potentially reduce native biodiversity by creating near-monocultures. Not mowing your lawn and allowing these plants to spread can create weed pest problems that people on neighboring properties likely will have to manage with herbicides.

You will find pollinators on lawn flowers, but looks can be deceiving.

Some nonnative lawn plants are very attractive to pollinators. Thistle, crown vetch and, to a lesser degree, dandelion and white clover are commonly visited by bees. This attractiveness helps invasive plants get pollinated, set seed and spread effectively.

But the pollinators you see on these nonnative plants are already the most common in the landscape. Adding these plants to a landscape does not improve North American pollinator communities or support biodiversity.

The dominance of a few pollinator species on these plants may indicate that human influence has reduced the number of species in that ecosystem. Typical human-altered landscapes have a small number of cosmopolitan weedy plants – species found in a broad range of habitats in many parts of the world – and a handful of pollinator species.

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