Your Lawn Questions, Answered – The New York Times
Who knew that the lawn — a generic landscape element that we basically manage on autopilot — could be so provocative? The recent In the Garden column “Yes, You Can Do Better Than the Great American Lawn” elicited nearly 1,200 comments, and a few key themes resounded, prompting a follow-up.
In that story, Daniel J. Wilder, an ecological horticulturist at Norcross Wildlife Foundation in Massachusetts, suggested some environmentally focused changes that we can make in the way we care for our lawns, as well as a few lawn alternatives for those ready to eliminate some or all of their turfgrass.
Each possible change, he suggested, could help move the needle from a monoculture of mowed, nonnative grasses to a landscape that gives back more to the ecosystem, in terms of pollen, nectar and seed, while using less water and fuel — and fewer chemicals .
But even his simplest suggestions, including mowing less often, raised questions. What about homeowner association rules, a number of commenters asked, that forbid a less-than-manicured front lawn? And what about ticks?
Does a Taller Lawn Mean an Enhanced Tick Habitat?
Assessing the relative risk of encountering a tick in a particular place is a two-part equation, said Felicia Keesing, a professor of biology at Bard College, in Annandale-on-Hudson, NY. The answer has to do not just with the habitat we ‘re in, but with our behavior in that space.
dr Keesing is one of the authors of a recently published study, The Tick Project, which investigated whether reducing the number of ticks in an area necessarily meant reducing the number of tick encounters experienced by humans — and if it decreased cases of tick-borne disease.
The team she led with Richard S. Ostfeld, a disease ecologist at the Cary Institute of Ecosystem Studies, in Millbrook, NY, studied yards in Dutchess County, NY, an area with one of the nation’s highest rates of Lyme disease. The five-year project involved the participation of some 3,000 people and 1,000 pets in 24 neighborhoods.
Consistent with observations from a 2006 study observing tick density along forest-field edges, the team found fewer ticks in grassy areas than in wooded ones: Ticks were about eight times more abundant in forests than in lawns, across all the properties studied. (In the 2006 study, the space in between, or ecotone, where herbaceous habitat meets forest, had a tick density somewhere in between.)
But that’s not the only relevant factor.
“When we’re talking about your risk of exposure, we are talking about two things,” Dr. Keesing said. “At work are both the entomological risk — how many ticks there are in the habitat — and also how much time you’re spending in that habitat.”
The high density of ticks in wooden areas won’t affect you very much if you don’t spend much time in the woods. But the ticks in your lawn could, despite their lower density, if you spend a lot of time there.
To determine whether reducing the number of ticks reduces human risk, Tick Project team members deployed two products known to be environmentally safe. The first was Met52, a spray derived from a naturally occurring fungus that infects ticks. The second was Fipronil, a chemical in pet-protection products like Frontline: A baited box held a wick treated with the chemical; mice would brush up against the wick, and any ticks that bit them would die.
The study involved 24 neighborhoods, and the participating properties in each neighborhood all got one of four treatments (and nobody, including the researchers, knew which one): active fungal spray, active bait boxes, both or neither.
The bait boxes treated with Fipronil did the best, reducing the total number of ticks by about half, and also reducing the incidence of disease reported in pets. But consistent with other studies, reducing the number of ticks did not correlate with a reduction in human disease cases. dr Keesing speculated that perhaps because pets engage with more of a property than people do, they derive a greater benefit from a decreased tick population.
“In all these years of research on prevention strategies, we collectively — the tick research community — have never found an intervention that actually reduces cases of tick-borne disease in people,” Dr. Keesing said.
One area of research that invites more focus, she added, is the relative effect of mowing frequency and grass height on tick density. Mowing less frequently can benefit the environment, but will it mean more ticks, as many commenters feared?
A two-year study of 16 suburban yards in Springfield, Mass., published in 2019 by US Forest Service researchers, tested whether mowing frequency influences the prevalence of ticks. Lawns were mowed at one-, two- and three-week intervals, with grass heights reaching from just over 2.5 inches to more than 10. There, even the tallest lawns, which were mowed less frequently, were not found to have ticks.
What would larger studies elsewhere reveal?
One thing is certain, Dr. Keesing said: Whether you’re mowing every week or once a month — or even if you’re planting a lawn alternative — you need to practice scrupulous self-care tactics and pet checks to protect against tick-borne disease. Simply keeping your lawn short won’t offer a free pass against risk.
The Risk of Not Diversifying
Calling the tens of millions of acres of lawn in America “an ecologically dead status symbol,” Douglas W. Tallamy, an ecologist at the University of Delaware, encourages us to do better and help regenerate biodiversity by planting more natives.
And that means replacing some of our lawn.
In his 2020 book, “Nature’s Best Hope: A New Approach to Conservation That Starts in Your Yard,” he challenged readers to help create what he calls a Homegrown National Park. His proposal: that a network of individual efforts can add up, and will help to offset the fragmentation of the greater landscape.
Now, in an online Homegrown National Park campaign, participants can commit their land to the movement by joining an interactive map and displaying a sign that tells neighbors what they are doing.
It’s time, Dr. Tallamy said, to “bring the private landowner back into a critically important position in the future of conservation.”
He isn’t calling for the wholesale removal of grass. As he points out, grass is functional — “the best plant to walk on without killing it” — and it sends the right signal. A bit of lawn conveys that a yard has not been forgotten, but is a landscape with intention that could inspire others.
“One reason I don’t say to get rid of the whole lawn is that it’s a cue for care,” Dr. Talmy said.
He regularly hears from those who would like to join the campaign, but are limited by homeowner association covenants that require a mowed front yard.
There is a national movement to reduce the power of homeowner associations, he said, citing examples like the May 2021 legislation passed in Maryland that prohibits rules for bidding “low-impact landscaping,” such as habitat-style, pollinator or rain gardens.
“The era of HOA overreaching is ending,” he said.
He suggested two approaches to help accelerate that change. Join the active management of the association, and educate from within, or set an example by rethinking your front landscape: Leave some lawn, but add native plantings.
“Make those changes in an aesthetically pleasing way,” Dr. Talmy advised. “The lawn you keep along the edge of your driveway or sidewalk — again, a cue for care — should be manicured and mowed regularly. That shows that whatever is beyond that mowed strip is an intentionally designed landscape. Typically, HOAs don’t object to that.”
As for tick worries, creating more native habitat has a benefit there, too.
“Our simplified landscapes are not only poor at producing ecosystem services like supporting local food webs, managing watersheds, nourishing pollinators and sequestering carbon,” he said. “They also do not provide habitat for the animals that decrease tick infectivity, because they are dead-end hosts for Lyme disease,” and play no role in the disease-transmission cycle.
“The more types of mammals you have in your yard, the better for creating sustainable balance,” he added.
But he knows that many people are hesitant to make their yards even a little wilder.
“We’re so divorced from nature that we think we don’t even need it,” Dr. Talmy said. “But nature’s not optional, and it’s worth the risks. It’s a matter of managing the risks.”
More Resources for Native-Focused Gardeners
Looking for inspiration and ideas for native alternatives to the conventional lawn? Whenever you’re dealing with native plants, local advice is key.
Start by identifying your nearest native plant society and exploring its website for regionally appropriate plant suggestions, recommended sources and information about meetings and educational events. The North American Native Plant Society lists such organizations in each American state and Canadian province.
Another nonprofit membership group to join and learn from is Wild Ones, with chapters in 27 states.
The Xerces Society for Invertebrate Conservation provides regional plant lists and sources for native seed and plants in various regions.
Audubon and National Wildlife Federation have ZIP code-based native plant search tools, as well as online shopping.
Margaret Roach is the creator of the website and podcast A Way to Garden, and a book of the same name.
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