GROTON -- "Kill Your Lawn" was the unfiltered message from Mark Richardson, New England Wildflower Society's Botanic Garden Director, when he spoke to a full house at the Nashua River Watershed Association Sunday afternoon. The talk was cosponsored by the Groton Garden Club and funded by a grant from the Groton Trust Funds' Lecture Fund.
"Though we need some lawn for recreational and high foot traffic areas, we need to rethink the default American landscape, and find better ways to manage our lands, large and small," Richardson said.
With 40+ million irrigated acres, lawns are the largest agricultural crop in the country. Because turf grasses are non-native, cool weather plants, they are always under stress. Americans spend $40 billion dollars to keep them thriving.
In New England one third of our clean, piped, treated water goes to lawn irrigation. The number is 60 per cent in the dryer West. The average lawn service applies 5-7 lbs/acre of pesticides. The highest pesticide use in agriculture is 2.5 lbs/acre for sweet corn fields. Richardson shared a chart showing the health risks of many commonly used lawn pesticides.
"You can't have a perfect lawn in New England without fertilizer. And all fertilizers are potential pollutants, as they run off into the waterways," he said. "In Massachusetts, phosphorus fertilizers are restricted on lawns unless a soil test shows them to be necessary."
A lawn mower running for one hour is the same as driving a car 100 miles.
"The 'Anywhere America' lawn landscape is a boring and sterile monoculture," Richardson said. "It's not biologically diverse. In the middle of a hot summer day, who wants to spend time on the lawn?"
A solution to these drawbacks is to grow plants that do not need water, fertilizer or pesticides, plants that are adapted to the New England hydrology, soils, and climate. Those plants are native plants. Richardson outlined ways to get rid of the lawn and add native lawn alternatives.
Chemical herbicide methods are the fastest, but Richardson stressed even organic chemicals are not necessarily safer. Clear plastic left on the lawn will solarize, or steam pasteurize an area in about 6 weeks. Most recommended is the application of a single layer of cardboard with compost mulch topping. This method of lawn removal takes about a year but it builds a healthier soil.
Then there is the benign neglect method: Stop mowing the lawn. Let it go. Leave the leaves. Remove problematic weeds. Over-seed with a perennial wildflower mix and/or plant perennial plugs.
Alternative native lawn plants include Wild Strawberry, Prairie Dropseed, and Pennsylvania Sedge, which can be mowed. The salt and drought tolerant Purple Love Grass, Bearberry, and Three-Toothed Cinquefoil like full sun. Spreading flowering plants like Wild Blue Phlox, Foam Flower, Canada Windflower and Round-Leaved Groundsel provide color and a unique sense of place.
Mark Richardson and Dan Jaffe also have a book release in March: "Native Plants for New England Gardens."