Botanical Threats to Greenway Meadows--Neighbors Raise Concerns

Over the years I've sung the praises of Greenway Meadows, the park in western Princeton with an asphalt trail running down the middle of an expansive meadow. One post describes the beauty of broomsedge and cross country racers "testing inner nature in a natural setting." Another describes the exhilaration of riding a bike through the meadow on the way to an art exhibit opening at the Johnson Education Center.

More recent visits to Greenway Meadows have focused on the threats to the park posed by invasive species, and the need to act quickly, before the problem gets overwhelming. This past April, it was dramatic to see how lesser celandine is beginning to invade the meadow and the lawn.

Then this summer, Mimi Schwartz, who lives near Greenway Meadows, reached out about the park. She had noticed some attrition among trees along the Poetry Trail, and wondered if competition from the tangle of invasive shrubs growing beneath them might be a cause.

Another neighbor of the park, Jennifer Widner, is focusing on threats to the meadow--threats that surely go unnoticed by the many people who walk or jog down the asphalt trail, see a pleasing green, and look no closer.

Still apparent to all are the many native wildflowers in the field, among them common milkweed and wild bergamot. 

But on a visit to meet Jennifer, I was astonished to see the extent to which Sericea lespedeza (aka Chinese bushclover, Lespedeza cuneata) is beginning to dominate. This is an invasive species that has become a big problem in the southeast U.S. and the plains states, but was comfortingly rare in Princeton when I first moved here in 2003.

There are various species of native bushclover that can sometimes be found mingling with other wildflowers in a field, but Sericea lespedeza doesn't, as they say, "play well with others." It's behavior is more that of a bully.

In understanding the threat posed, it helps to have lived elsewhere in the country where Sericea lespedeza has had a longer track record of aggression. Living in Durham, North Carolina, near where the species was first introduced, in 1896, and is still widely used for erosion control despite many efforts to have it banned from seed mixes, I witnessed its capacity to displace native species. 

For those who say live and let live, and let it be, consider the ecological consequences if the meadow ultimately becomes a monoculture of an introduced plant with indigestible seeds and inedible foliage. Here's one fact sheet's description:

"Sericea contains a high concentration of tannic acid, which causes wild and domestic animals to avoid eating it, unless no other food is available. Animals then forage more intensely on native plants, which depletes the desirables and allows invasives to increase. Tannic acid leaches from sericea into surrounding soil, creating a toxic environment that prevents or slows the growth of other plants, giving it yet one more advantage."

Mimi and Jennifer have had some success engaging public officials on these threats, and the land managers at DR Greenway's headquarters nearby are potential allies. 

The project with the clearest solution is the freeing of trees from the invasive shrubs growing beneath. A greater challenge, requiring intervention and vigilance for years to come, will be stopping uber-invasives like lesser celandine and Sericea lespedeza. 

My experience, though, is that the work can get easier year to year, as steady effort makes the invasives less numerous. Down the road, or down the trail, as the threat recedes, those involved may get to experience that wonderful "walk in the park" feeling, where the botanical bullies have been sent packing, and require only a bit of ongoing vigilance and mild intervention to prevent their return.

For more information on Sericea lespedeza, try these: BlueRidge and Oklahoma State.

Related post:

Monocultures in the Making - 2013