No Mow May in Massachusetts: Does It Really Help Bees?

By mid-May on the South Coast, lawns that were left alone start to change color. Dandelions, violets and the first white clover open in the grass, and bees find them within hours. No Mow May asks homeowners to let that happen on purpose. It’s a simple idea, and it has spread quickly across Massachusetts, but the research behind it is less tidy than the slogan.

Quick answer: No Mow May is a campaign that asks people to skip mowing their lawns in May so flowers like dandelions, violets and clover can bloom and feed early bees. It started with the UK charity Plantlife in 2019 and reached Massachusetts towns such as Sudbury and Somerville. It helps most in lawns that already have flowers. A Massachusetts study found that mowing every two weeks all season supported the most bees.

What is No Mow May?

No Mow May is a pause on lawn mowing for the month of May. The idea is that lawns full of “weeds” are really full of flowers, and that early-season bees, waking up when few gardens are in bloom, can use them. Plantlife, a British conservation charity, launched it in 2019 alongside a citizen science survey called Every Flower Counts. The first big U.S. adopter was Appleton, Wisconsin, in 2020.

Which Massachusetts towns do No Mow May?

Several, and the list changes year to year:

• Sudbury: the town’s Energy and Sustainability Committee has encouraged residents not to mow until the end of May.
• Somerville: the city has paused mowing of some city-owned grassy areas during May.
• Pittsfield: Berkshire Community College has joined in.

Many other towns, garden clubs and conservation commissions promote it informally. Check your town’s website or conservation commission each spring, and if you have a homeowners’ association, check its rules before you let the grass grow.

Does No Mow May actually help bees?

It can, but it depends on your lawn. The campaign’s best-known evidence was a 2020 study from Appleton, Wisconsin, that reported more bees in unmowed yards. The journal retracted that study in 2022 after finding inconsistencies in how the data were handled, and its authors maintained that their overall conclusion still held.

Other researchers have pointed out a practical limit: if a lawn is nearly all grass, leaving it uncut doesn’t produce many flowers. A one-month trial at the Guelph Turfgrass Institute in Ontario found unmowed Kentucky bluegrass plots didn’t support substantially more flowers than plots mowed at 2.5 inches. No Mow May helps most in lawns that already have dandelions, violets and clover in them.

What did the Massachusetts lawn study find?

The most useful research comes from Springfield, Massachusetts. Susannah Lerman and colleagues followed 16 suburban lawns over two summers (2013 and 2014), mowed every one, two or three weeks, and published the results in Biological Conservation in 2018. They recorded 4,587 bees from 93 species visiting lawn flowers.

• Lawns mowed every two weeks had the most bees, though not the most species.
• Lawns mowed every three weeks had the most flowers, up to 2.5 times more clover and dandelions, but fewer bees than the two-week lawns, possibly because the taller grass made flowers harder to reach.
• Lawns mowed weekly gave bees the least to work with.

The takeaway is that mowing a bit less often, all season long, may do more than one month off. The Xerces Society, a pollinator conservation group, calls No Mow May “a starting point, not the finish line.”

Is there a downside to not mowing in May?

Two, mainly. The first big mow in June can kill insects that settled into the tall grass, so it’s worth mowing gradually or raising the blade for that cut. The second matters a lot on the South Coast: ticks. Ticks like tall grass and shady, humid edges, and May and June are peak season for the tiny nymphs that spread Lyme disease. Keep a short-mowed strip along paths, play areas and the edges of the yard, and check yourself and your pets. Our post on ticks on the South Coast has more.

What can you do for bees besides skipping a month?

1. Mow every two to three weeks from spring to fall, and set the blade higher.
2. Let clover and dandelions bloom. Skip the weed-and-feed, which kills both. Our post on whether to pull dandelions explains the trade-offs.
3. Turn a patch of lawn into flowers. Even a 10-by-10-foot bed of native perennials feeds bees from spring to fall. Our guide to planting a bee-friendly garden has a bloom-time plant list, and coastal yards can use our list of pollinator plants for coastal yards.
4. Skip insecticides on the lawn, especially when anything is in bloom.

Honeybees fly up to a few miles from the hive, so the flowers in your yard feed bees from all over the neighborhood. Read how far bees travel.

Frequently asked questions

When did No Mow May start?

The UK charity Plantlife launched No Mow May in 2019. Appleton, Wisconsin, became the first U.S. city to adopt it in 2020, and Massachusetts towns including Sudbury and Somerville have since encouraged it.

Is No Mow May good or bad for bees?

It helps bees when a lawn already has flowering plants like dandelions, violets and clover. It does little for a lawn that is almost all grass. A Massachusetts study found that mowing every two weeks all season supported the most bees.

How often should you mow for bees?

About every two weeks. In a Springfield, Massachusetts study published in 2018, lawns mowed every two weeks had more bees than lawns mowed every week or every three weeks.

Does No Mow May increase ticks?

Tall grass gives ticks more of the shady, humid cover they like, and May is peak season for tick nymphs in southeastern Massachusetts. Keep paths and play areas mowed short and check for ticks after time outdoors.

What should I do after No Mow May ends?

Mow gradually. Raise the mower blade for the first cut, or mow in sections a few days apart, so insects have somewhere to move. Then keep mowing every two to three weeks rather than going back to weekly.

Sources

• Lerman SB, Contosta AR, Milam J, Bang C. “To mow or to mow less: Lawn mowing frequency affects bee abundance and diversity in suburban yards.” Biological Conservation, 2018. DOI
• The Xerces Society, “No Mow May: A Starting Point, Not the Finish Line.”
• Plantlife, No Mow May and Every Flower Counts.
• Town of Sudbury and City of Somerville, No Mow May announcements.
• Undark, “There’s Little Science Behind ‘No Mow May’,” 2024 (Guelph Turfgrass Institute trial and the Appleton retraction).

Whether you skip May or just mow a little less, your lawn’s dandelions and clover are on the menu for bees. That’s a good use for a lawn.