Once some formerly desirable perennials start spreading in your garden, killing out other plants and taking over, they become “weeds.” This term is relative to individual desires of a gardener, and growing conditions and climate. A plant that may be aggressive in one area or one person’s yard, may not be in another.

Then there is the term “invasive” seen much in recent years. This is often tied to whether a plant is native or not, but more importantly reflects its behavior. The problem is that invasive plants disrupt natural habitats and displace native species. Often such native species are food sources for wildlife.

It is estimated that about one-third of the plant species found in the state are non-native. Of these only about 8 percent have the potential to disrupt natural habitats. Many non-natives are either beneficial and economically important (such as the state flower, the red clover), or have no impact (such as the mullein and Queen Anne’s Lace wildflowers).

Most states have lists of invasive plants, or ones that may potentially be so. For a federal listing of plants and photos, visit the Natural Resources Conservation Service Plants Database (plants.usda.gov). Such state, regional and federal lists are good places to visit even before buying plants, but especially before pitching them from your garden where they may escape into natural areas.

Watch plant and catalog descriptions too when buying, and use caution with plants described as “aggressive” or “spreading”. Watch the cultivars (cultivated varieties), as some of a species may be spreaders or seeders and others not.

In either our general weeding when these invasives get thrown in with the other garden debris, or in our rage to get them out, we don’t think where we end up dumping or pitching them. Often this is in a nearby field or woods where the invasive roots and seeds may become established. Invasive perennials can then take over those natural areas, killing out established and desirable plants there. This is especially true if we dump the debris near waterways, which carry the root pieces and seeds into wetlands.

So how do you control these invasive exotic garden plants, and get rid of them? Begin by learning which species may be invasive and don’t buy them in the first place. If you already have them in the garden, don’t merely pitch them into natural areas with other garden leaves, clippings or debris. Composting may not kill the seeds and roots, and these invasives may even take root in a compost pile! Burning may be the best option, but check your local community for burning ordinances. Bagging and carting to your local waste or recycle center is often recommended for such “thugs” in your garden. Contact or systemic herbicides may also be applied to them if desired, but be sure and follow all label directions when using such chemicals. And it may take more than one application.

Other means to prevent invasive plants from entering wetlands include never releasing aquarium plants into natural waterways. Inspect ornamental aquatic plants, such as waterlilies, that you order through the mail. This is especially true if the plants come from the southeastern U.S. states.

So once you have invasive plants, think before you pitch. And before buying plants, get armed with information on which may become invasive. Your local full-service garden store should be able to help you with this, and with suitable alternatives.

For a pdf booklet of South Carolina’s invasive plants compiled by Clemson Extension, go to http://www.se-eppc.org/pubs/scbooklet.pdf

Courtesy UV Extension