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Saturday - February 23, 2013

From: Norfolk, VA
Region: Mid-Atlantic
Topic: Groundcovers
Title: Groundcover for strip on street from Norfolk VA
Answered by: Barbara Medford

QUESTION:

My house is on the east side of a north/south street. Between the curb and sidewalk is a strip about 3' wide, with two crepe myrtles spaced about 20' apart and a mix of sparse weeds and grass leaving a lot of bare dirt exposed between the trees. The city owns it but I'm responsible for maintaining it. It's where I put my garbage can and recycling bin on trash day, and when someone parks on the street they walk across it. I want to put a native groundcover in that will cover up the bare soil and prevent erosion onto the street. I was thinking of Pennyslvania sedge (Carex pennsylvanica), but the thing is, up to a dozen times a year the street floods during a heavy storm and the water goes up past the sidewalk for a few hours. Since Carex pennyslvanica prefers dry soil, I'm worried that will kill it. Is this a suitable place for the Pennsylvania sedge? If not, what's a good alternative?

ANSWER:

Frankly, that would be a hostile environment for just about any groundcover we can think of. Foot traffic, trash cans and flooding are a lot to ask a plant to tolerate. If the dirt is level with the curb, our suggestion might not work, but if the level of the dirt is lower than the sidewalk and curb, we would suggest some nice round river rock. Not gravel, as this would be just as likely to wash away in the flooding as dirt or plants. You don't want to pave it over because that would deny oxygen and nutrients from the soil around the roots of your trees. We often suggest mulch as groundcover for difficult situations like that, but mulch would be down the street and into the ocean in the first hard rain.

Often the best plant for holding soil and preventing erosion is a grass of some sort. Carex pensylvanica (Pennsylvania sedge) is not a true grass but is grasslike. Grasses are good because they have long fibrous roots that can anchor the plant and help hold the dirt in place. Unfortunately, those long fibrous roots are going to take a while to develop and if you have that many floods every year, it seems unlikely that any plant would be able to get itself properly established in time to do you some good. The rounded rock would have spaces around it to permit water and air to get to the tree roots; of course, that would also permit a certain amount of weeds to creep up, but vigilance and a little pulling out should take care of that.

Here are links to some articles with suggestions for a rock groundcover:

Decorative Ground Cover Rocks

How to Use Rocks as a Ground Cover to Control Your Weeds

Using River Rock for Ground Cover