The weekend before last I had the pleasure of meeting Heather Holm, a great gardener and leading advocate for pollinators from Minneapolis. She has self-published two very useful (and attractive) books: Pollinators of Native Plants (2014) and the multiple-award-winning Bees: An Identification and Native Plant Forage Guide (2017).
Heather told me about her own lawn, which she has overseeded with fine fescues and now mows just three times a year, with a reel mower set to the highest mowing height. This more meadow-like condition has encouraged flowers from her surrounding beds to infiltrate. As well as two species of violets, her lawn now sports woodland phlox, wild geranium and avens. The net result has been to transform this area from a green desert (biologically speaking) to a happy refuge for pollinators.
This is one area of the landscape where even a small change in maintenance can have a big impact. A study by US Forest Service of 16 suburban lawns in Springfield, Massachusetts found that reducing the frequency of mowing from weekly to once every two weeks can have a dramatic impact on the turf’s attractiveness to bees. This is because weeds such as clover and dandelions that were routinely decapitated had a chance to bloom when mowing was postponed for just one week. Presumably, it was the pollen and nectar these flowers offered that increased bee visitations to the lawn by slightly more than a third. The diversity of the bees was impressive, too – the researchers identified 93 different species of bees visiting these small patches of turf.
This should just be a beginning. Why not deliberately introduce wildflowers into our lawns? I have naturalized Crocus chrysanthus, snow crocuses, in my lawn and because the grass, like Heather Holm’s, is a mixture of fine fescues that needs mowing only a couple of times a summer, the crocuses have performed as true perennials, returning year after year. I planted these flowers because I love the very early spring color they provide, but they are also a fine early food source for bees and other pollinators. The tiny bluets (Houstonia caerulea) that have colonized my turf on their own are also an early food source, mostly for small bee flies as well as native bees.
In an era when grasslands are disappearing from much of the Northeast, lawns could provide a refuge for grassland flowers and their pollinators. I’ve been planting violet wood sorrel into a small patch of sheep fescue (Festuca ovina) in the front yard of our Berkshire cottage. This meadow flower, once common in Massachusetts, is now found in only six wild colonies state-wide. My hope is that my lawn can provide a seventh.