Kudzu present along a nature trail along the Hudson River.
Every forest has an edge; at that edge, you’re likely to find vines. Some grow straight up into the canopy, climbing over tree branches to get there, some grow across the ground and through the herbaceous level, and a few (often a forester’s least favorite) wrap around the trunks of trees tightly, winding their way to sunlight. Our forests of the northeast have grown up in co-evolution with many species of vines: grapes, moonseed, trumpet creeper, American wisteria, and the oft-maligned poison ivy have been here for centuries. However, the forest faces brand new threats in the non-native vines that have been brought over for landscaping purposes. These vines have few insects and other herbivores that target them, and as a result, threaten trees across the state.
The most famous invasive vine nationally is Kudzu. “The Vine That Ate The South” has gotten hungrier as time has gone on and now there are 40+ sites where Kudzu is located in Southern New York. Identifiable by its three pronged leaf and brilliant purple flower, Kudzu was used for erosion control and livestock forage in the south and is now firmly rooted (no pun intended) in that region. In New York, Kudzu has not had a historical presence and is still at a stage where we can stop it from spreading, though its unmatched growth rate of up to a foot per day makes it a serious threat. If you have seen Kudzu, you can report it to the DEC at (845) 256-3111, where they will request pictures to confirm the location.
The most common invasive vine in New York thankfully grows a little bit slower. Oriental Bittersweet is a woody vine that wraps around the trunks of trees as they grow, choking out the tree slowly but surely. Identifiable by its orange roots, this vine has extremely circular leaves and can be found almost anywhere in the state. It makes attractive red fruits that are encapsulated in an orange covering in the late fall that are present throughout the winter and eaten by birds, who then spread bittersweet across the countryside. To combat this plant, the entire root must be removed from the ground, which is complicated by its extreme horizontal growth in the root system and habit of snapping off when pulled. Herbicide is often the quickest way to deal with larger vines, painting the cut stump of large bittersweet immediately after cutting it is a good way to ensure that the same vine isn’t threatening the same tree the next year, though cutting alone can be a help, especially when the stump is in a shaded area.
Swallowworts come in two varieties, pale and black. They are difficult to tell apart when vegetative, but grow five-petaled, star-shaped flowers in either purple-black or pinkish-white coloration depending on the species. These flowers bloom in mid-summer, often at the start of June at our latitude. This species is of special concern due to its effect on pollinators: monarch butterflies think that it is milkweed and lay eggs on the leaves, resulting in caterpillars that consume this poisonous plant. Since it is related to milkweed, it produces bean-like seed pods that burst open with fluffy seeds that are spread by the wind. This has resulted in the Hudson River being one of the main corridors that this plant has used to facilitate its spread, all the way north into the Adirondacks. It is also notoriously hard to remove manually, though a foliar spray application of herbicide can do the trick.
Japanese Hops is either new to the Albany area, or we may have just started paying closer attention in recent years. This is not the hops that produces beer, it’s a five-lobed, non-native variety that has small hooks on the bottom of the large leaf. Sometimes mistaken for Bur Cucumber, the species have very different fruit and hops is identifiable by those hooking hairs previously mentioned. Bur cucumber also has spiraling tendrils that reach out to find new places to grow. Fortunately, this is another vine that does not have a strong presence in the region right now, so it is especially important to report this one to your local PRISM.
I unfortunately don’t have the space to cover all the invasive vines that threaten our trees, they are quite numerous. Not making the cut (pun intended), I encourage responsible forest owners to research other threats to their property, such as chocolate vine, non-native wisterias, wintercreeper, mile-a-minute vine, periwinkles, porcelainberry, English ivy, sweet autumn clematis, and Japanese honeysuckle. Fragmentation of our forests has opened plenty of power lines, roadsides, and property boundaries which make perfect vine habitat due to the increased sunlight that is now present for the opportunistic plant to take advantage of. Often, humans are responsible for bringing these quick-growing species here and it will take a concerted effort on our part to stop these plants from taking over these areas and then our backyards. If there are any questions regarding the management of non-native vines, don’t hesitate to contact your local PRISM office.
Pale Swallowwort growing in Malta, NY.