Friday, April 8, 2011

Buyer Beware... Avoiding Invasive Plants

How many times have you bought a new type of plant for your landscape and later discovered that it was considered an aggressive or even an invasive species? Chinese Wisteria, English Ivy, Chinese Privet, Burning Bush, Vinca… all of these carry the invasive label and characteristics, though they can also be easily found at plant nurseries. So what exactly makes a plant invasive?

First, they are exotic plants. These plants were not native to the area they now readily grow in. Ironically, some species such as Kudzu and Multiflora Rose were actually once recommended for erosion control and living fences, respectively. They now are the bane of millions of North Carolina residents. True, there are some native plants that have aggressive tendencies, but they are not considered to have the same threat level as invasive plants.

Exotic invasive plants do not support native wildlife. The mountains of North Carolina are an incredibly rich, diverse ecosystem. When native plants disrupt the natural balance of plants growing in an area, this has subsequent effects on birds, amphibians, mammals… the web of life.

Invasive plants tend to also have extreme growth, whether through the ability to vegetatively spread or by producing massive amounts of seed. Excessive growth of these invasive plants outcompetes native plants, literally “choking” our native plants out of room, light, and soil nutrients and water. Some invasive plants actually release natural compounds from their roots to prevent other plants from germinating and growing.

There are several intriguing arguments regarding invasive plants. It is true that many of our common edible crop plants are not “native”, though most don’t tend to have invasive characteristics. Inevitably, when we build a new home and convert natural areas to neighborhoods, businesses, or roadways, we are disrupting the ecological balances… and invasive plants excel at taking advantage of those disrupted sites. Yes, some invasives can be utilized for food purposes, and some are very ornamental and fragrant. However, the extreme ways in which they alter our native ecosystem are dramatic and largely negative. Consider the loss of our native hemlocks, which are being killed by a tiny invasive insect that was carried over from Asia on a non-native hemlock species.

As a landscaper, gardener, and resident of North Carolina, it is in our collective interest to avoid the intentional spread of invasive plants. The NC Native Plant Society ( provides a comprehensive list of invasive species and their respective threat levels. This list was compiled by research professionals from a variety of state organizations and should be referenced before purchasing or planting any new plant into the landscape.

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