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.
Leaf tips will bronze in the middle of the growing season when a tree is infested.
Oak wilt resurfaced in Glenville this year. After battles with this invasive tree pest in the town in 2009 and 2013, DEC flyovers revealed another site in Sanders Preserve, and a neighbor’s vigilance brought to light another site in a residential neighborhood. Considered one of the worst forest pests that New York is currently battling, oak wilt is a huge concern for the forestry community and could have devastating impacts on all species of oak found in the state.
Oak wilt was first identified in Wisconsin in the 1940s, but may have been present in the U. S. before that. Currently its affects are most strongly felt in the Midwest and Texas, though the range expands upwards north into PA. It is currently reported in New York in Brooklyn, Long Island, Glenville, and Canandaigua. Fortunately there are few enough locations that the DEC has been running an extermination campaign, working to eradicate this fungal disease when it appears in upstate areas. The door-to-door outreach took place on two cold mornings in January, notifying homeowners within a half mile area of the two sites about the pest and its symptoms. The public meeting (attended by 49 Glenville residents) to announce the eradication plans was on January 31st, and the goal is to have the infected trees removed by April 1st.
Now at this point you may be asking, what exactly is oak wilt? It is a fungal infection of all species of oak trees, though its effect is most visible in the red oak family, where it can kill a tree in a matter of weeks. It is most visible through the leaves of the tree, which start to bronze uniformly at the tips like they were dipped in paint. These leaves often start to fall off the tree, still green, around the fourth of July. The symptoms have been described as a “tree heart attack,” clogging the transport mechanisms through the tree with the fungus. Species in the white oak family are not immune either, though they exhibit less symptoms they can be passive carriers of the fungus.
One of the reasons that this is such a difficult pest to manage is that there are a few ways that the disease spreads. Locally, the fungus can spread through the root connections between trees, most present in trees of the same species, though links between different kinds of oak species are also common. This is the reason a buffer zone of trees is often cut when treating for oak wilt, there can be asymptomatic trees within root-reach of obviously infected trees. The disease can also ‘jump’ up to five mile through a common species of beetle, which after feeding at a fungal tree, go to a fresh wound (often caused by pruning or construction) on a healthy tree. For this reason, it is recommended that trees be pruned in the winter, and not in the months of March-September. The DEC diagnostic laboratory is preparing for a monitoring project later this year to determine the most active time of year for this beetle to make more exact pruning recommendations to both homeowners and arborists.
PRISM staff have been working to help the DEC with outreach efforts regarding oak wilt. If you think that you have a tree that is infected on your own property, the DEC runs a hotline at (866) 640-0652 which you can call to have a DEC technician come take a sample of the tree in question that will be tested at the labs at Cornell. Community involvement is huge when taking on a tree disease of this magnitude. The oak is one of the most ecologically important trees in our state, providing animals with food throughout the winter through its acorns, supporting a vast number of insect herbivores with nutrients, which then in turn feed our birds. While it is hoped that the efforts in Glenville puts a stop to the northern movement of the fungus, it is important that all forest owners keep an eye out for the symptoms in their woodlots in order to protect oaks on their property, and statewide.
An infested tree showing heavy bronzing during the summer.
Whether it’s a small hobby farm or a large scale farm, all farmers should be aware of the invasive species that can be growing in their fields. Just a few are Jimson Weed, Canadian Thistle, and Russian Knapweed. All are similar because they overtake overgrazed pastures, barnyards, and fields.
Jimson Weed is an important invasive for farming operations; it is poisonous to all livestock animals. Not only can it be a problem in underused fields, overgrazed pastures and in the barnyard, but it can also be a problem in crop fields, particularly soy beans. Farmers should be watch out for this plant and taking appropriate measures to make sure that it’s not present where animals are grazing. They will most likely avoid it because of the odor and taste, but in sparse pastures, they could be tempted to consume it if they are hungry enough. If the farmer is producing hay and silage they should make sure that all the Jimson Weed has been removed prior to harvesting because this can contaminate the feed, making the animals sick. The seed of Jimson Weed can contaminate grain which most commonly effects chickens. The use of herbicides is the most effective way to eliminate Jimson Weed, just remember to take proper precautions. Although many animals have gotten sick from Jimson Weed, it is more common for humans to get sick from this plant. Children especially because they think the flower is pretty and end up ingesting it.
Canadian Thistle is another common invasive species in fields. It reduces pasture capacity and forage as well as overtaking native species. It can produce up to 3,000 seeds annually and the seeds can last in the ground for up to ten years. This plant can be poisonous to livestock, but only in large quantities, therefore Jimson Weed is a bigger concern for the animals. This is a tough plant to get rid of, therefore a foliar herbicide plan should be used in both the spring and the fall. Stinger is a product that is relatively specific to thistles and knapweed that has been shown to be effective on this plant. Mowing before the flowers come out is also beneficial, but they plant can flower multiple times during the season. Pre-flower mowing just once will not help decrease the amount of plants. Farmers should also know that tillage stimulates growth and can cause more seeds to spread and more plants to grow.
Last but not least is Russian Knapweed. This stubborn plant is slow to start, but once it is established it can spread aggressively. It can produce up to 1,200 seeds per year. Livestock generally avoid this plant because of its taste but it isn’t good for them to ingest in hay. Horses are especially sensitive if they consume Russian Knapweed because it can cause a fatal neurological disorder that affects the muscles that allow them to swallow. This puts the horse at risk for starvation. To help remove this plant from pastures, herbicides can be helpful. Farmers can mow in two to three intervals before the seeds set to decrease seed and shoot production. They can also use deep cultivation to help eliminate this plant however do not use shallow cultivation.
These are just a few out of the many plants that can cause harm to field production as well as livestock. Farmers should be aware of these plants due to their effects on animals.
-Jess Holmes, Capital-Mohawk PRISM Project Assistant
One species that tends to get people's attention when it comes to invasive species is Japanese Barberry. This species, commonly used for landscaping around homes and businesses, comes in different colors and shapes, which make it such a popular shrub. It provides a barrier between properties, with the added security of small thorns that run up and down the stems. However, the reasons that it has become so popular in our cultivated landscapes are also reasons that this plant is one of the most widespread invasive shrubs on the East Coast, and a prime vector for Lyme Disease.
Lyme Disease has been well documented as a problem here in the East. The Center for Disease Control calls it one of the fastest growing diseases in the U.S. and a significant reason for this increase is due to the invasive plants clogging up our forest understories. Plants such as Japanese Barberry, Japanese Honeysuckle, and others are not browsed by the deer, which prefer the native plants surrounding them. this leads to increased space for these invasives to flourish. Lyme disease is commonly known as a tick-spread disease so many people may be left wondering, what do plants have to do with it?
Invasive plants make up so much of our forest biomass at this point that animals utilize them to the best of their ability. Though many native species skip over these invasives when looking for food, the low branches of barberry provide perfect habitat for two species, ticks and mice, which are the main vectors of Lyme. Mice are drawn by the cover and thorns that protect them from predators such as raptors, and the ticks are present in the foliage, waiting for a meal. The ticks latch on to the mice, where they acquire the bacteria that causes Lyme disease. The public health problem that we have with Lyme now started in our gardens in the 1800s.
Barberry has been popular due to its ability to tolerate a wide range of environments. It produces many seeds which then get spread by wildlife into our forests and fields. Its so popular in fact that many people became upset when it was finally downgraded to prohibited from its restricted designation. It is a best-seller in many nurseries, specifically because it is hardy and deer don't browse it. I have heard people say things like "well, maybe I'll go to Pennsylvania and bring some back," as if our NY forests did not already have barberry in spades. People in the nursery industry are hard at work trying to find an exception or cultivar to get past the regulations, or simply trying to get the species taken off the prohibited list. To me it seems that they are missing the point. It takes so long to get a species designated as prohibited, most often plants don't make it on that list until they have become a widespread problem. By designating a species as prohibited, the state is saying that they finally have enough evidence to conclusively prove that this species causes more problems then it has benefit, and people trying to get around these regulations in whatever way possible shows that Lyme Disease, ecological impact, invasive potential... those things matter less to them than having a shrub that they don't have to put that much effort into.
The state has said if you already have a barberry plant in your yard, you don't have to get rid of it. But on the other hand, if you value the nature of New York State or have kids that enjoy using that lawn without the worry of ticks and Lyme Disease... maybe it'd be best to grab a shovel or a pickaxe and take that invasive shrub out of the ground.
Don't miss that tap-root.
NBC New York is starting a five part series on Lyme Disease. You can watch the first part here.