Q&A: Pros and Cons of the No-Mow May Movement

Q: Do you have any information related to the “no mow” movement? We have a very weedy lawn and are considering replacing it with Dutch clover. Is that a good idea? Bad idea? 

A: We do not recommend replacing lawn outright with clover. Clover goes dormant in winter, losing leaves, which leaves the soil surface exposed to weed seed colonization and potential erosion. The clovers used in lawns are also non-native and would not support the majority of our native bees (which are specialists, relying on certain native species for pollen, nectar, or plant oils). Generalist bees can use clover or other blooms but these tend not to be the local bees needing the most support from garden plantings.

If you prefer to augment your existing lawn with clover, consider microclover, which is a dwarf and less-aggressive variety of white clover that cohabitates with turfgrass more cooperatively. While not solving any of the other above issues, at least this is a more suitable choice when using clover in a lawn. Our Lawns and Microclover page provides some pros and cons plus links to a more detailed publication (PDF document) about how to go about creating and maintaining this mix.

a flowery lawn with unmowed grasses
Chanticleer’s flowery lawn interpretation, more of a no-mow-ever than a no-mow May situation, and thus of more benefit to wildlife. Photo: M. Talabac

Opinions among professional horticulturists about “No Mow May” actions are mixed because there are both benefits and drawbacks that it creates. You will probably find both proponents and opponents to this practice in Extension and other science-based web publications and articles. The main benefit of the movement is its ability to get gardeners thinking about their landscaping choices and actions and the impacts of these on the ecosystem. (And that’s a good thing!) That said, most of the flowering lawn weeds that no-mow is supposed to protect are non-native and do not support many of our native bees, and allowing them to set seed only enables them to spread further in places where native plants should ideally be growing instead. 

For gardeners interested in having turf serve double-duty as a “bee lawn” – that is, intentionally planted with seed mixtures containing low-growing flowering plants – the benefits and shortcomings of this approach are similar to those with clover lawn conversions or from reducing mowing for limited periods of time. University of Minnesota research shows that bee lawns do provide benefits for pollinators, including native ones. However, most commercially-available bee lawn mixes contain plants from Europe and/or Asia, and are perhaps not the best nutritionally for Maryland’s specialist bee adults or a resource they will be able to use for their young. Some Maryland native plants that can be incorporated into bee lawns, such as Self-Heal (Prunella vulgaris subspecies lanceolata), are not readily available in seed mixes here, and research on Maryland-native plants for use in bee lawns is not available at this time. Visit UMN’s “Planting and Maintaining a Bee Lawn” web page for more detail.

Our energies and efforts aimed at benefiting insects, birds, and other organisms may be better spent creating native plant gardens alongside of (or in place of) lawns, which will not only serve specialist bees more suitably but also will support a variety of other native wildlife in the process. In any garden setting, including when plant selections are native-focused, using a diversity of plant species has several benefits: it can support a greater diversity of wildlife (including pollinators and beneficial insects that help suppress pests), it adds aesthetic and seasonal interest, and it increases the resiliency of the planting as a whole, because different species won’t have the same degree of vulnerability to any one issue (like drought or flooding) that may arise.

white flowers of fleabane in bloom
 Native common fleabane (Erigeron philadelphicus) blooms in a front yard where a portion of the turfgrass was removed and replaced with little bluestem, switchgrass, and a mixture of flowering perennials. Fleabane supports a variety of native bees, solitary wasps, and other beneficial insects. Photo: C. Carignan

Not mowing lawns regularly also stresses the turf by creating a situation where, when mowing does resume, it’s removing much more of the turf’s leaf mass at one time, causing stress and interfering with its normal growth habit that creates a dense lawn. The “grazing response” that mowing triggers, promoting more low growth that fills-in gaps, won’t be happening to the same extent if the grass goes for weeks without being cut, especially as it diverts some energy for growth into producing pollen and seed. (This turfgrass flowering also might be a consideration for people with bad grass pollen allergies.)

This topic of bee resources in lawns as addressed by the no-mow movement is touched upon by wildlife biologist Sam Droege in the native bee special episode of the University of Maryland Extension Garden Thyme Podcast from last summer.

Lawn alternatives, even if not purely native species, are another option when dealing with a lawn that is struggling. While a healthy lawn is providing more environmental services (carbon sequestration, erosion control, nutrient filtering, etc.) than a struggling lawn, if you do not wish to devote resources to improving its health and vigor, then converting those areas to non-lawn is more practical, even if a bit more expensive at first than just rehabbing the lawn. If a tolerance to regular foot traffic from people or pets is needed, then lawn is the best groundcover for this use and you might want to work to improve its health, but otherwise areas not being stepped-on can be planted with other species.

By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.

Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-roundYou can also connect with your local County/City Extension Office and Master Gardener local programs.