DATE: 1/6/05

CONTACT: Dr. Larry Nelson, (864) 656-4866

WRITER: Tom Lollis, (803) 284-3343, ext. 241

Clemson publication will help public identify invasive plants

CLEMSON – You probably knew that kudzu is a problem plant, one that is officially designated as invasive. Did you know that Japanese honeysuckle and wisteria are also considered to be pests?

Those three are on the top 10 list of Invasive Plant Pest Species of South Carolina, which happens to be the name of a new publication from the Clemson University Department of Forestry and Natural Resources and the South Carolina Exotic Pest Plant Council.

“We’re trying to create more awareness of invasive plant species in the state, let people know where to go for help and what they can do to help control them,” said Larry Nelson, Clemson University Extension forester and treasurer of the South Carolina Exotic Pest Plant Council.

In addition to honeysuckle, kudzu and wisteria, the top 10 list also includes: Chinese tallow tree, autumn olive, Chinese privet, Japanese stiltgrass, multiflora rose, common reed and wart-removing herb.

The top 10 are on a list of 34 pest plants, grouped by growth form – trees, shrubs, vines, grasses and sedges, and herbs. They are:

TREES – Severe threat: Chinese tallow tree; significant threat: tree of heaven, mimosa or silktree, Chinaberry and princess tree.

SHRUBS -- Severe threat: Russian olive, thorny olive, autumn olive, Japanese privet, Chinese privet and multiflora rose; significant threat: two-color bush clover (Bicolor Lespedeza), leatherleaf mahonia, Cascade Oregon grape and nandina or sacred bamboo.

VINES – Severe threat: Japanese honeysuckle, kudzu, Chinese wisteria and Asian wisteria; significant threat: English ivy, Japanese climbing fern and beach vitex.

GRASSES AND SEDGES – Severe threat: Japanese stilt grass and common reed; significant threat: giant reed, bahia grass, bamboo, Chinese silvergrass and tall fescue.

HERBS – Severe threat: wart removing herb; significant threat: nodding thistle or marsh thistle, bull thistle, Japanese knotweed and tropical soda apple.

Color photos are included to help with identifying the top 10 invasive plants.

“Exotic species are those that have been imported to this country,” said Nelson. “Not all are invasive. For example, most of our agriculture crops are nonnative species.”

He said that experts estimate that for every 1,000 species imported, about 100 escape cultivation and 10 of those are likely to become invasive.

Plants on the invasive species list are not ones Nelson would recommend to South Carolina homeowners for landscaping.

“They are capable of moving from site to site, with the potential of taking over a site completely at the expense of all other species,” Nelson said.

Nevertheless, a number of exotic species that are becoming invasive are still available through gardening outlets and catalogs. Wisteria, honeysuckle, the olive group and Chinese privet are just a few examples.

“Eventually we’ll have to encourage such outlets to curtail the sale of these plants,” Nelson said.

The number of brochures is limited for the time being. A few copies will be distributed to each county Extension office, and the brochure will eventually be placed online at the Clemson University website.

Nelson has also back ordered copies of a book entitled “Nonnative Invasive Plants of Southern Forests: A Field Guide for Identification and Control.” By James Miller, research ecologist with the USDA Forest Service at Auburn University, the book will be available free of charge. It should be available in the next two months.

“It includes really good photos of the major invasive species of forests in the 13 Southern states and recommended control measures,” Nelson said.

“Anyone who has a large acreage of an invasive species will probably have to contract control out to a certified pesticide applicator,” he said. Small populations can be controlled by using a backpack sprayer, following recommended application methods and rates.

END