Biodiverse Lawn

Biodiverse Lawn

Guest Post by Tom Christopher (before he became a regular)

Like other members of the Lawn Reform Coalition, I believe that the contemporary model of lawn has got to go. It does have its virtues, though we critics tend to overlook them. For example, traditional lawn provides a relatively inexpensive and easy way to maintain large expanses of the landscape in a green and domesticated cover – I can think of no other landscape treatment aside from meadow that can cover an acre or two of sunny ground and demand only a couple of hours a week of maintenance, and though I prefer the beauty and biodiversity of a meadow, it is not appropriate for heavily trafficked areas. Lawn also provides a nearly ideal play space for children and a relatively tick-free zone – an important benefit where I live, 30 miles from Old Lyme, Connecticut, the original epicenter of the Lyme Disease epidemic.

What if we could eliminate many of the environmental defects of lawns while preserving its benefits? That was the question I asked myself 5 years ago, and one that I have been exploring ever since. Other types of cultivated landscape used to be environmental disasters but have since been updated. When I began my career as a horticulturist 40 years ago, rose gardens were toxic from the constant application of pesticides, but that has changed with the introduction of disease- and pest-resistant cultivars, and a more environmentally sophisticated style of design and maintenance. Likewise, the average vegetable garden was dependent on constant inputs of synthetic fertilizers and pesticides a generation ago. Could the lawn be similarly updated, I wondered.

My first pursuit was to identify types of grasses that in the Northeast where I live that are less demanding of mowing, fertilization, irrigation, and pesticides. A few emails put me in touch with turf breeders at Rutgers, Cornell, and the University of Connecticut who very generously shared the under-utilized low-maintenance turfs that they had created. A visit to Dr. Stacy Bonos at Rutger’s turf-breeding station was particularly eye-opening.

Bluets in the lawn.

Bluets in the lawn.

I soon came to focus on mixes of different fine fescue cultivars as the most promising alternative for my purposes. Once established on a site, such blends require mowing no more than 2-3 times a year, they are drought-resistant and much less hungry for nitrogen, and, if the cultivars are chosen with care, naturally weed- and insect-resistant. However, I found these blends challenging initially because they are slow-growing (that’s why they require so little mowing) and so slow to establish.

It has taken several years of experimentation, but I have developed a routine that will convert a conventional lawn to fine fescues in just 6 weeks at a price customers can afford, and which, with occasional interventions, produces an mature, mostly weed-free lawn within 6 months.

By “weed-free” I do not mean that such a lawn is a grass monoculture. In fact, the sustainable lawn model I have been seeking demands a more diverse flora. In this case, I am defining “weeds” as plants that make the lawn unsightly, increase the need for mowing, and which will overrun their neighbors. The best way to keep such plants out of the lawn is to fill their niches with other, more turf-compatible plants. My inspiration for this came from first-hand experience, of course, but also readings in guides to lawn maintenance dating back to the pre-chemical-care era – one such book from the 1920’s, for example, included more than two dozen flowers it recommended including in the lawn.

White clover (Trifolium repens) provides an obvious example of the benefits such plants can provide: not only does it enhances soil fertility but it also flourishes where soils are too poor to support vigorous grass growth, and continues to grow in conditions of heat and drought that push most northern lawn grasses into dormancy. And of course clovers are a nectar source for bees.  Strawberry clover (Trifolium fragiferum) also integrates easily with turf grasses, providing similar benefits to those of white clover and pretty flowers.

christopher violets 2

Violets in the lawn.

Our native violets and even Viola tricolor add color and coexist quite comfortably with turf, providing food for a variety of moth and butterfly caterpillars. Houstonia caerulea, bluets, are also compatible and quite pretty and help to feed a variety of native bees.

Other plants that I have identified include Trifolium repens atropurpureum, the bronze Dutch clover (I want to create a turf networked with its colorful foliage), Thymus serpyllum (creeping thyme), Fragaria virginiana (wild strawberry), and Potentilla indica (Indian strawberry). Some of these are native while others are not, but I use the exotic species only where they are already naturalized and non-invasive. I’ve also incorporated early spring flowering, low-growing bulbs into my lawns, including the early crocuses, snowdrops, grape hyacinths, etc. as they have gone dormant by the time the fine fescues need their first mowing.

I would like to expand this list of lawn-compatible forbs, and I am asking for your suggestions. Ideally, any such plants should be easy to start by direct seeding, as this will help to keep my sustainable-lawn model affordable. In addition, they must be sufficiently low-growing that they do not increase the need for mowing, and they should be either perennial or reliable self-seeders.

I am aware that many members of the Lawn Reform Coalition will object to continuing lawns in any form. I myself was of that position for many years, but what I found was that friends and customers often did not have the time, resources or commitment required to transform their landscapes so fundamentally. According to a NASA study, lawn is, like it or not, the largest irrigated crop in the United States, covering an area equal to that of the states of Virginia, Massachusetts, Connecticut, Rhode Island and ¼ of Vermont combined. If we can make an immediate impact on this, reducing its resource-use and turning it into a carbon-sink rather than a CO2 generator, wouldn’t that be worth doing?

Tom Christopher’s pioneering sustainable lawn company is aptly named Smart Lawn.  Tom’s the author of Water-Wise Gardening, a guide to new styles of gardening, editor of the wonderful New American Landscape, and more.   Tom also writes for HuffingtonPost and contributes to a blog about sustainable gardening, Green Perspectives. It’s a product of the New York Botanical Garden, where Tom earned his degree in professional horticulture.