Most Southern Illinoisans are familiar with honeysuckle.

It's a benign-looking plant. There are no thorns and the sweet fragrance of the waxy-white flowers is a harbinger of spring.

It's also an invasive species.

Honeysuckle is now one of five plant species that is illegal to sell or distribute in Illinois.

"People just kind of accept it as part of the flora now," said Jody Shimp, an Illinois Department of Natural Resources biologist. "If you sample some of our forests, it's a co-dominant species."

Although invasive plant species don't grab the headlines, they are as much a problem as animal species.

"Animal species are probably much more obvious and much more economically driven," Shimp said. "Good examples are the gypsy moth and the Japanese beetle. The Asian carp is another good example. They just seem to have more of an impact."

That's not to say invasive plants aren't a problem.

Annual plants such as Japanese stilt grass and garlic mustard are two plants getting plenty of attention from biologists. Japanese stilt grass was first identified in Southern Illinois in 1967, but has now worked its way into most of the region's designated natural areas.

"It's one of the most invasive plants we have," Shimp said. "Few people in Southern Illinois are familiar with it. Any road down in Pope County, the roadside is covered with these things."

Japanese stilt grass is also known as Chinese packing grass. Shimp said the plant was used as packing material for goods shipped from the Orient. Seeds made it into the wild and the grass is now out-competing native species in some areas.

Garlic mustard has also risen to the top of the IDNR's most-targeted list.

"For a long time we didn't have much of it," Shimp said. "Now, it's just about in every county. We've just finished a survey. It has to get to a certain level where people and animals can get to the seed.

"Once it gets to a certain level, the chance of contaminating your boots and moving it increase."

Garlic mustard produces large amounts of seed. Currently, biologists are fighting the plant by burning plants with propane torches to inhibit seed production.

Shimp said the possibility exists that an aphid could be introduced to control garlic mustard.

"It used to be a real iffy thing," he said. "Today, they really have to go through a rigorous testing approach to make sure it doesn't affect our native plants. I think they have it down to where there are fairly low risks." Autumn olive, multi-flora rose and phragmities are other species being targeted by IDNR.

Autumn olive is one of the easier invasives to control. It thrives in open areas, but doesn't do well as the forest closes in around it. In addition, it is a shallow-rooted plant. Eradication efforts include uprooting and follow-up prescribed burns.

"At Pyramid State Park, we're really trying to be aggressive with it," Shimp said. "You have to get the roots out of the ground and follow up with fire."

Phragmities, a tall plant resembling cane, is also under attack at Pyramid and at the new Sahara Woods site.

Although the fight against invasive plant species doesn't garner headlines, Shimp said the state is serious about controlling these species.

The IDNR and Southern Illinois University are forming a coalition with 11 area counties to form a management agency. Shimp said such coalitions are common in western states.

He said the partnerships make it possible to receive more federal dollars.

les.winkeler@thesouthern.com

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