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College of Food, Agricultural, and Environmental Sciences


Properly Manage Invasive Plant Species at Farm Science Review

August 5, 2010

Editor's note: Photo captions: No. 1: Honeysuckle spreads across a forest floor. The invasive plant is the first to green up in the spring and the last to die off in the fall, preventing native plants from taking hold. No. 2: A grove of Callery pear overtakes a field near Slyvania, Ohio.

LONDON, Ohio – Some invasive plants may look pretty and smell heavenly, but they can wipe out native plant species and can have a detrimental impact on the ecosystem if not properly managed.


Visitors to Ohio State University's Farm Science Review will learn what it takes to keep invasive species under their thumb. Farm Science Review will be held Sept. 21-23 at the Molly Caren Agricultural Center in London, Ohio.

"Many invasive species have found a niche in Ohio," said Kathy Smith, an Ohio State University Extension forestry specialist in the School of Environment and Natural Resources. "A hands-off management approach may result in a woodland ecosystem where the invasives dominate the stand."

Smith will present "Invasive Plant Species in Ohio's Woodlands" on Sept. 21 from 10:30 a.m. until 11 a.m., Sept. 22 from 2 p.m. until 2:30 p.m., and Sept. 23 from 11:30 a.m. until noon.

Invasive species Smith will discuss include honeysuckle, ailanthus, autumn olive, garlic mustard, buckthorn, privet and Callery pear. She will explain how to identify each species, why they are a problem and what the control options are.

Honeysuckle, for instance, will outcompete native plants and reduce the possibility of trees regenerating in the understory of our wooded areas.

"Honeysuckle is the first to green up in the spring and the last to go dormant in the fall, so there is little room for other plant species to get a foothold," said Smith. "As the trees in the canopy die off all that may be left is honeysuckle, and more honeysuckle."

In addition, it produces red berries that birds will eat, but the berries hold little nutritional value.

"Honeysuckle is junk food for wildlife. Migrating birds that would normally rely on native plants for food are now getting something that provides them with lower nutritional value food that results in lower energy reserves," said Smith.

A new honeysuckle hybrid is being found in Ohio – the showy fly honeysuckle – that produces beautiful magenta flowers. It is a cross of two other honeysuckles already present in Ohio – Morrow and Tartarian.

"The flowers really grab people and they say, ‘Oh, how pretty. I would love to have that in my yard'," said Smith. "They are struck by the scent and the beauty, with no concept of the offsite impacts this plant will have.

Autumn olive is another problematic invasive species that was originally introduced because of its ability to fix nitrogen in the soil and its berries for wildlife.

"Autumn olive was thought to be a great plant to grow in areas like reclaimed strip-mine land," said Smith. "Unfortunately it doesn't stay where you plant it."

Garlic mustard was originally introduced as a cooking herb but it can now be found prolifically throughout Ohio.

"People shrug their shoulders as to why they should care that garlic mustard is taking over our woodlands," said Smith. "But tell them that if you don't control the garlic mustard, then the forest floor loses its wildflowers and many of its mushrooms and that seems to get their attention."

The latest in the growing list of invasive species, which many still don't consider to be a nuisance, is Callery pear.

Callery pear was introduced as root stock for ornamental pears. ‘Bradford' Callery pear was heavily used as a landscape plant with many aesthetically pleasing attributes along with being unable to reproduce. The problem began when other cultivars were introduced and started to cross pollinate with ‘Bradford'.

"You drive into Columbus during the spring when the pears are blooming and they appear to be everywhere," said Smith. "Once established, they dominate a site just as most of the invasive species do. There are places in Ohio where there are groves of pear so thick you can't walk through them and each of those plants has the ability to reproduce."

Smith said that recognizing invasive plant species is important to understanding the impacts they have on the environment and understanding what would happen if native species became extinct.

Several resources are available to help Ohioans identify invasive species, including the Ohio Invasive Plants Council website (, the U.S. Department of Agriculture "Guide to Non-Native Invasive Plants Inventoried in the North by Forest Inventory and Analysis," the U.S. Forestry Service "Invasive Plants Field and Reference Guide" and a series of OSU Extension fact sheets for woodland owners.

"These invasive plants were brought to Ohio for a variety of good-intended reasons," said Smith. "We just didn't know what they would do."

Farm Science Review is sponsored by the College of Food, Agricultural, and Environmental Sciences, Ohio State University Extension, and the Ohio Agricultural Research and Development Center. It attracts upwards of 140,000 visitors from all over the country and Canada who come for three days to peruse 4,000 product lines from 600 commercial exhibitors and learn the latest in agricultural research, conservation, family and nutrition, and gardening and landscape.

Farm Science Review pre-show tickets are now on sale for $5 at all OSU Extension county offices. Tickets will also be available at local agribusinesses. Tickets are $8 at the gate. Children 5 and younger are admitted free. Hours are 8 a.m. to 5 p.m. Sept. 21-22 and 8 a.m. to 4 p.m. Sept. 23.

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Candace Pollock
Kathy Smith