By Allen Bernard, Ohio Chapter Volunteer

 

You can cut it. You can burn it. You can even douse it with herbicides. But the one thing you can't do with Japanese honeysuckle is get rid of it. This seemingly harmless vine, imported from eastern Asia in the early 19th Century to ornament the homes of New York City's wealthy, is as tough as it is beautiful. Since its introduction, Japanese honeysuckle has escaped its artificial boundaries and spread over most of the southern and eastern United States.

 

According to Marleen Kromer, director of Interagency Program Development for the Ohio chapter of Nature Conservancy, Japanese honeysuckle has been around for years. "People have planted it for quite a long time. What we find with a lot of these invasives is that you're probably not going to eliminate them totally," she said.

 

Eradicating this invasive would require an all out war that is probably unwarranted anyway. Although an aggressively spreading species, Japanese honeysuckle (Lonicera japonica) is not as bad as other invasives like tree-of-heaven, which has taken hold in every county of the state.

Japanese honeysuckle is a woody semi-evergreen vine with opposite oval leaves. It sprouts pairs of lovely white-to-yellow, funnel shaped flowers from April through June and pulpy berries that turn purple-black when ripe in early fall.

Japanese honeysuckle is a climber and will cover anything nearby to get closer to the sun; it will readily spread out as ground cover, burying its roots deep. This is one of the reasons it is so hard to eradicate. The root system is tough, extensive and runs deep underground. If a vine is pulled and roots remain behind, the plant reacts aggressively by sending out dozens of new shoots.

Few natural boundaries keep this invader in check. It spreads quickly, favoring disturbed areas like roadsides, abandoned home sites, fencerows and forest gaps. It prefers sunny conditions but, like any good invader, it can also take hold in marginal habitats. In fact, it can create forest gaps for itself by covering entire trees, causing them to fall from the added weight. Once a gap is opened in the forest canopy, the plant thrives. Because of its growth rate and ability to create its own ideal habitat, Japanese honeysuckle edges out native species by limiting sunlight and out-competing them for nutrients and water. It also stands up well to drought because its waxy leaves retain moisture.

That's the bad news; the good news is that, although we may not eradicate it, we can control this pest. Hand pulling will work in small, limited areas containing relatively few plants. Mowing can also reduce plant size, but will not remove it and can lead to extensive root suckering. Grazing -considered the only biological control- will have about the same result as mowing, but with less predictability.

 

Controlled burning is another option, but this must be done carefully so as not to damage desirable species or property. Use of fire must be continued over many years to achieve maximum results. If burning is discontinued, Japanese honeysuckle will likely grow back after several years.

According to the Illinois Department of Conservation, chemical control via Glyphosate herbicides like Roundup, Glypro, Garlon 3A or Garlon 4 is recommended. Herbicides can be used during the growing season, but care must be taken not to harm other native species that will move into the area after the honeysuckle is eliminated. Because Japanese honeysuckle is semi-evergreen, it will continue to photosynthesize after many native species go dormant in the late fall. This is the best time to hand-apply chemicals since it will minimize damage to the surrounding native species. This should be done before the first freeze, when Japanese honeysuckle stops growing.

"As with a lot of these invasive plants, sometimes they become a real problem in a local area," Kromer said. "I've had it my yard and if I don't cut it back every year ... by the end of summer [the fence] is totally grown over.

"If you're just working in your backyard," she said, "you might have a good chance of totally eliminating honeysuckle...either by being persistent about digging it up all the time and cutting back all the runners and vines on a regular basis, or you could use herbicides."

With total eradication unlikely, it seems we will have to learn to find the balance of preventing future invasions, minimizing the spread of current populations, and accepting some amount of infestation in natural areas.