Love the Look and Feel of Grass? These Ground Covers Are for You.

Plus, how to honor an Olmsted-inspired historic landscape with a native turf replacement.

Newly planted trees and turf in the1920s (Source: Preservation Farmington)

Dear Avant Gardener, I am having an area of backyard against my house regraded and want to use the opportunity of fresh soil to begin transitioning from non-native turf to a walkable, native groundcover. What do you recommend? May I start with a portion of my lawn if I'm not ready to rip the whole thing out yet? When can I plant it? And where can I find seed? — Zoe, Hudson Valley, NY

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Running barefoot in the grass feels awesome. I discovered this at age three when I visited the suburbs: “I’m running in the grass! I’m running in the grass!” I yelled in delight, according to my mother. I wasn’t allowed on the grass around our Manhattan apartment building. 

Few native groundcovers reproduce the fantastic foot feel of conventional lawns made of grasses from Africa, Asia, and Europe. That’s why I love Pennsylvania sedge (Carex pensylvanica) and path rush (Juncus tenuis). Both are drought tolerant once established, stand up to foot traffic, and require little or no mowing and no fertilizer or chemicals. And they are hosts to beneficial native moths and butterflies. In fact, according to the Native Plant Trust, Pennsylvania sedge is a pollinator powerhouse. 

Pennsylvania sedge, native east of the Rockies, thrives in shade where traditional turfgrass languishes. (For lawn-replacement sedges native elsewhere, see “Sedge Lawns: A Sustainable, Low-Maintenance Alternative to Grass.”) Sedges are difficult to grow from seed, so plant plugs in fall or spring (available at Mid Atlantic Natives).

Lesser-known path rush is native to all North America. You can plant seeds now and they are available from various sellers online, including Ernst near you. See the excellent description and planting info at Everwilde in California.

And certainly start with part of your lawn if you’re not ready to rip it all out. Most lawns are already a mix of plant species, anyway.

Dear Avant Gardener, Which plants grow well under a silver maple and black walnut trees? We live in a house that is 100 years old and I believe the lawn, both of those trees, and a catalpa are also 100 years old. The trees sap a lot of nutrients from the lawn, so I would do an anti-lawn if I could find a good-looking plan. After reading “The Overstory” and “Finding the Mother Tree,” I know the importance of finding the right plants to work together. Any ideas? — Karla, Farmington (near Detroit)

Instead of an anti-lawn, why not pick a ground cover that honors both the historic character of your home and the plant communities that developed there long before it?

When your house was built, the auto industry was booming and middle managers were moving to new suburbs like Farmington seeking “modern, substantial houses architecturally and physically distant from the city.”¹ The lawn-and-tree yards surrounding their homes were likewise a refreshing change from the intricate beds of exotic flowers in Victorian gardens.

This “pastoral” style was inspired by English estates and championed in America by Frederick Law Olmsted. And it remains the dominant suburban landscape aesthetic, much to the detriment of native wildlife. Ironically, given his legacy of 40 million acres of exotic turfgrass, Olmsted himself not only disliked lawn mowers, but preferred native plants:

Turf, for example, is to be in most parts preferred as kept short by sheep, rather than lawn mowers; well known and long tried trees and bushes to rare ones; natives to exotics; humble field flowers to high bred marvels. — Frederick Law Olmsted, 1886

You can create an ecologically rich pastoral yard by replacing the turfgrass under your trees with Pennsylvania sedge. It thrives in maples’ dry shade and tolerates black walnuts’ juglone (more below). And has that "green, dripping, glistening, gorgeous” look Olmsted admired in English turf. 

If you prefer to introduce some height or texture, ferns will also thrive in your conditions, as will other sedges. Masses of one species or two or more similar species will most closely suggest the Olmstead look. Christmas fern (Polystichum acrostichoides), hayscented fern (Dennstaedtia punctilobula), eastern wood fern (Dryopteris marginalis), and lady fern (Athyrium filix-femina), for example, thrive in dry shade. You can find many ferns and sedges during open retail days at wholesaler Wild Type Native Plants in Mason, MI.

Piling this fall’s maple and walnut leaves eight or more inches high to the trees’ waterlines will kill the current turf. You’ll be ready to plant plugs into the leaves in the spring.

— The Avant Gardener

Why, How, Wow!

Why

Silver maple and black walnut trees, both native east of the Rockies, present different challenges to plants beneath their canopies. Maples (Acer spp.) have dense canopies and shallow, expansive roots that together create dry shade. You want small, drought-tolerant, shade-loving plants with shallow roots to plant under maple trees. 

On the other hand, walnuts (Juglans spp.) produce a substance that oxidizes into juglone, poisonous to many plants – and black walnuts (Juglans nigra) have the highest concentration.

As part of its strategy to outcompete other plants for space, nutrients and light, the black walnut produces hydrojuglone which, when exposed to air or soil compounds, oxidizes into juglone. Juglone is biologically active, acting as a respiratory inhibitor to some plants. This kind of chemical action is called allelopathy, the suppression of growth of one plant species by another due to the release of substances. While other trees produce allelopathic chemicals to suppress another (e.g. the American beech suppresses the sugar maple, its co-dominant partner through its leaf leachate to achieve a balance in their co-existence), the black walnut is best known for this efficient chemical. — The Black Walnut – A Study

How

Wow!

I was introduced to path rush by Michael Butts, co-owner of Bluestem Gardens, who designed and installed the plantings in my Brooklyn garden. Michael was growing path rush, among other things, in his role as bulk seed manager for Greenbelt Native Plant Center. The center has supplied native plant seed and plants for the restoration of city-owned land, making  New York City “the greenest city on earth.” That’s even more “Wow!” than the beautiful garden he created, below.

Path rush and Pennsylvania sedge (longer, around circle) in my Brooklyn garden

Related Resources

• Curious about the books that inspired today’s questioner to find plants that work together? Check out the 2019 Pulitzer Prize for Fiction “The Overstory,” and New York Times best-seller “Finding the Mother Tree: Discovering the Wisdom of the Forest.”

• Want to learn more about sedges?  Sam Hoadley, manager of horticultural research, will be sharing the top-performing species from Mt. Cuba’s Trial Garden and discussing how to incorporate them into home gardens on February 1, 2023, from 6 to 7:30 p.m. Register for this online event at  Carex for Every Garden.

  

1. From Motor City to Motor Metropolis: How the Automobile Industry Reshaped Urban America, by Thomas J. Sugrue