WHO KNEW Simple Changes in Lawn Care Produce Fascinating Results?

A few years ago, Susanne Lerner, a researcher at UMass, visited the Upper Valley to share her fascinating research on lawns. In 2014 and 2015, 17 volunteer homeowners in Springfield, MA, agreed to allow Susanne and her team complete control over the care of their lawns.

The researchers mowed the lawns between May and September using push mowers and mowing at various time-intervals with a mower height of 2.5”. Grass clippings were left on the ground to decompose and feed the grass. No lawns were watered, fed or chemically treated. They counted the flowering plant varieties that appeared within the grass, as well as the bee varieties that visited these plants.

On lawns mowed less frequently, they discovered 111 species of bees. Most of the bee species were native to North America (94.6%), nested in soil (73%), and were solitary (48.6%). They found 63 plant species in the lawns; the majority were not intentionally planted. The most abundant lawn flowers were dandelion and clover. Nearly 30% of the spontaneous plant species growing in the lawns were native to North America

The researchers also learned that, compared to lawns mowed once a week, lawns mowed every three weeks had as much as 2.5 times more lawn flowers than other mowing frequencies. Similarly, lawns mowed every two weeks had high bee abundance but fewer bee species.

These results suggest that a ‘lazy lawnmower’ approach to lawns results in the greatly improved bee numbers and increased flowers. For some, mowing less often is more economical, practical and timesaving than lawn replacement.

Worried about an increase in dandelions? You can mow them after they bloom, while the seed pod is still enclosed. Dandelions are one of the earliest plants to bloom and, therefore, are a critical source of food for bees in the early spring.

Worried about bee stings? Most stings come from yellowjackets (a wasp), paper wasps and honeybees (not a native bee). Most native bees are ground nesting and docile.

Sources: The study, “Bee Fauna and Floral Abundance Within Lawn-Dominated Suburban Yards in Springfield, MA”, by S.B. Lerman and J. Milam, is found in ‘Annals of the Entomological Society of America, 109(5), 2016, 713–723‘ In a second study, Lerman focused on mowing frequency: Lerman, S. B. et al. 2018. “To mow or to mow less: Lawn mowing frequency affects bee abundance and diversity in suburban yards.” ‘Biological Conservation. 221: 160-174’