Tip of the Week: Replace Area After Invasive Removal

Posted in Gardening Tips on September 27 2010, by Sonia Uyterhoeven

Sonia Uyterhoeven is Gardener for Public Education. Join her each weekend for home gardening demonstrations on a variety of topics in the Home Gardening Center.

For the past two weeks I have written about the invasive Japanese stilt grass: describing it, exploring its life cycle, and giving tips on how to remove it.

Like most big problems, this annual grass will not go away easily. Repeated treatments are needed and the area needs to be maintained to discourage the plant’s growth. While this may sound daunting, it is reassuring to know that all you have to do is follow some simple and healthy gardening practices to slow down the return of stilt grass.

Most invasive plants are opportunists—colonizing areas that have been disturbed. So whenever you pull out any invasive plant, the first line of defense is to tamp down the disturbed soil (gently firming it with your feet).

If you are not replanting the area, the next course of action is to apply a thick layer of mulch over the surface. This will inhibit the germination of weed seeds uncovered in the soil disturbance and will provide a protective layer to prevent any introduced seeds from settling the area.

If you are planning on reseeding or planting the area, then do so as soon as possible, from several days to a week after removal. Plant thickly to fill in the empty space and to make it difficult for the invasive to reestablish itself.

Difficult areas can be filled with native plants that are effective colonizers. One example for a shady wooded area is hay scented fern (Dennstaedtia punctiloba), which is unstoppable and will rapidly cover an exposed area. Be sure when making these decisions that you are not replacing one problem with another.

If you are not planting immediately, fill the space with a nurse crop, a short-lived crop that can smother out potential problems. Such cover crops are planted to prevent erosion, reduce weed infestation, and, in the case of leguminous crops, to fix nitrogen in the soil. A mix of hairy vetch and winter rye is a good late season combination. If you are clearing an area in the summer, buckwheat is an excellent warm weather cover crop that can be turned into the soil at the end of the season.

If you are reseeding a lawn make sure to use a seed mix that includes some species of grasses that establish quickly such as perennial ryegrass in the fall.

Whatever options you choose, remember that if the area is left barren it will be an invitation for reinfestation.