May is a month of dramatic growth and change in Wisconsin landscapes. Throughout the month, especially during a late-arriving spring, many shades of green appear and deepen as ground layer plants reach full size and the tree canopy closes. Small ephemeral wildflowers emerge, bloom, set seed, and may even die back, disappearing until next year. Robust vegetative growth of summer- and fall-blooming plants begins. In the garden this month, we trim back last year’s plant material and pile it in nearby areas, where remaining dormant insects can emerge. We watch bees foraging and establishing nests, seeds germinating, and plant buds opening on twigs and bursting out of soil.

In May, cool-season grasses grow vigorously and may begin to flower. Examples include native blue-joint grass (Calamagrostis canadensis) in wet-mesic or wet soils, and June grass (Koeleria macrantha) on dry sites. Non-native examples of cool season grasses include reed canary grass (Phalaris arundinacea) an aggressive species that forms solid stands in disturbed wetlands, and Kentucky bluegrass (Poa pratensis), red fescue (Festuca rubra), and other turfgrasses, planted in lawns.

Many gardeners are interested in sustainable lawn care, with initiatives like No Mow May generating interest, participation, and conversations in many communities and the media. Most questions from homeowners (and reporters) ask how to improve landscapes in built environments to support pollinators and other wildlife. The question “is No Mow May part of the solution?” has opened broader conversations that reveal multiple ways to support pollinators, alternatives to turfgrass, and lawn health.

The ideal habitat for native pollinators and other beneficial insects is native plant garden beds and areas that are pesticide-free. We can foster their populations by planting densely with species that grow well in local site conditions, bloom sequentially throughout the season, provide larval foods, and support nesting. These areas – which can include non-native, non-invasive plants with proven insect and wildlife value – are managed with no mowing. In yards and parks, this can be accomplished by converting some or most lawn to native plantings. A gradual approach works best, within homeowner or landowner budget and time constraints.

In a lawn that has been managed with fertilizer and herbicide treatments, the start of a more sustainable approach would be to stop herbicide treatments and allow or seed small flowers like clovers, violets, and heal-all into the grass, creating a flowering lawn. This will provide some resource for pollinators while still providing open lawn space.

In a flowering lawn (or a traditional one), lawn health is promoted by cutting grass to three-and-a-half to four inches, instead of shorter. Each cutting should remove no more than one-third of the height. Allowing grass to reach six inches and cutting to four inches meets this guideline, which allows for less frequent mowing. Sometimes called “slow mow,” this pattern can be followed all season.

If you currently have a flowering lawn covering most of your yard, you can increase the wildlife value of your landscape by adding native plants in flower beds, introducing woodland plants under large trees, stabilizing slopes with native plants instead of turf, and/or creating native plant borders. This will reduce the area of lawn and eliminate mowing in those spaces.

For even more impact, share what you learn in this process with neighbors and community. Discover and photograph pollinators that visit your plants. Join Bumble Bee Brigade to learn more if you document bumble bees. Identify butterflies using wisconsinbutterflies.org and other invertebrates using bugguide.net. Also, sharing native plant seeds and gardening advice will amplify your efforts and inspire others.

—Susan Carpenter, native plant garden curator