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Here in Polk County, we have a tangled conundrum – of vines!

Kudzu is the biggest challenge in our county. Kudzu kills trees by depriving them of sunlight and, therefore, photosynthesis. The sheer weight of the vine makes the already-weakened tree susceptible to wind damage. Once a tree is toppled, its neighbors are further weakened due to the loss of wind protection. In terms of wind impacts, a grove/forest of trees acts as a single unit and the loss of one or a few trees compromises the remainder. A drive up (or down) US
176 between Tryon and Saluda is an eye-opener.

Kudzu has at least three other vine “friends” causing significant damage to the forest landscapes we all love. One of these invasives was imported from Europe, the other two from China, Japan, and Korea. We’re talking about English Ivy, Chinese Wisteria, and Oriental Bittersweet. Although there are several varieties of ivy, almost everyone knows it as English Ivy and knows what it looks like.

Chinese Wisteria has a beautiful magenta bloom at the top of the vine and is very aromatic. Although there are some native species of wisteria, where you see a number of vines it is almost always the invasive, Chinese, variety. Oriental Bittersweet is a less showy vine and doesn’t grow as fast as kudzu but is nonetheless fatal to trees. It has a gray stem and retains green leaves in the winter. Any invasives guide or a quick online search will help you identify it. Bittersweet and kudzu are often found together and their treatment and control are nearly identical. Chinese wisteria may or may not be co-mingled with kudzu and bittersweet, but it is controlled in the same way. In a new outbreak, kudzu and bittersweet can be a little hard to find. Not so with wisteria; the profuse blooms are a dead giveaway.
When any of these vines is dormant, it can be killed by cutting the vine and daubing the cut stem on the root side with an appropriate herbicide. This will kill the vine both above and below ground. Later in the season, once the vines leaf out the only way to control them chemically is through a foliar application of an herbicide. Vines, whether dormant or not can be killed by digging up the crown, which is located just below the surface at the base of the vine. Even though the crown is located near the surface, it can be large and difficult to remove. It can be hard, time-consuming, and tedious work, especially if done in the growing season when the weather is hot and nasty.

English Ivy is a different matter. Some people use English Ivy for landscaping or erosion control purposes. Ivy is appropriate for these uses IF it is continually maintained AND it is kept out of trees. Once ivy escapes, however, it goes everywhere. Look at virtually any older neighborhood in western North Carolina for evidence of this.

How can you protect the trees? Cutting the English Ivy vines at the base of the tree will kill everything above that point. The vines on the tree need not be removed; in fact, pulling recently-cut vines off the tree can cause damage to the tree. The cut vines will dry out within a matter of weeks, thereby reducing the weight borne by the tree and vastly reducing the risk of blow-down. And once the tree’s foliage is re-exposed to the sun, it can begin to recover its growth function. If the ivy on the ground at the base of the tree is not removed for a distance of a few feet around the trunk, the process will have to be repeated every two or three years so that the vines do not climb more than a few feet up the trunk before being repruned again. Fortunately, at this point, pruning is a quick and easy process.

Getting rid of a mat of ivy on the ground, if desired, does not necessarily require the use of chemicals, although chemicals can be effective. Hand-pulling ivy vines is very effective but is time-consuming (and tiring!). Any regrowth that emerges the next growing season is much easier to pull, and by the third growing season the vines should be virtually eliminated.

A note regarding herbicides. They are very effective at doing what they were designed to do – that is, to kill stuff. They often can kill non-target species of both plants and animals. The federal government requires that these products contain a label with the ingredients, target species, risks to humans and the environment, and conditions of use. For example, many herbicides are not appropriate near streams or other wet areas as they impact aquatic organisms. Some herbicides are more specific than others. Sonora (chemical name) affects only plants in the legume family, which includes kudzu. Roundup (Glyphosate) is equally effective on kudzu but also kills other plant species if it incidentally comes into contact with them. Read the label to see if the product is appropriate for your intended use — for your sake as well as the sake of the rest of the living environment.

Together as a community we can tackle it and help our forests return to its pre-kudzu condition as a mature forest. Start by eliminating invasive vines like kudzu on your property and working with your neighbors and local governments to eliminate them on public property.

Join the efforts of the Polk County Appearance Commission and Conserving Carolina’s Kudzu Warriors (https://conservingcarolina.org/event/kudzu-warriors-12/2024-06-24/) to chip in on helping our county tackle this green monster.

To learn more visit www.beautifulfoothills.org.

 

Submitted by Brian McCrodden, Polk County Appearance Commission

 

Oriental Bittersweet