Rewilding gardens may be growing in popularity but even a modest reduction in lawn mowing can boost wildlife, increase pollinators and save money, according to a study.
Researchers from the University of Quebec at Trois-Rivières found that reducing the intensity of trimming lawns in urban areas can also reduce pests and weeds that cause allergies.
A meta-analysis of data from 15 years of studies in North America and Europe found strong evidence that increased mowing intensity of urban lawns – including public spaces such as parks, roundabouts and road verges – reduced the diversity of plants and invertebrates.
Intensive lawn mowing also resulted in an increase in the abundance of weeds and lawn pests, according to data from eastern Canada.
Dr Chris Watson, lead author of the study published in the Journal of Applied Ecology, said: “These findings support a lot of research done by the turf industry that shows that the more disturbance a lawn gets, the higher the likelihood of pest and weed invasion.”
Watson cited common ragweed, a native of North America and highly allergenic plant, which is an invasive species in Europe, as an example of a plant that thrives under intense mowing. A Canadian study estimated that ragweed-based allergies cost $155m each year in Quebec.
Watson added: “Certain lawn invaders, such as ragweed, can be decreased simply through reducing lawn-mowing frequency. This will decrease the pollen load in the air and reduce the severity of hay fever symptoms, number of people affected, and medical costs.”
The study also estimated the economic costs of intensively-mown lawns, with a reduction in contractor costs if mowing frequency is reduced from 15 to 10 times a year.
“Although the potential ecological benefits are clear, reducing operational and public health costs may provide a greater incentive for decision makers to adopt lower-intensity lawn management,” the paper concluded.
Watson warned that local authorities were unlikely to reduce the intensive management of lawns without a change in public attitudes and an embrace of “messier” grassland.
“We need to shake the outdated social stigma that comes from having a lawn a few centimetres longer than your neighbour’s,” he said.