Invasive plants are defined as being non-native in the ecosystem they are found in, and their introduction can cause economic, environmental, or health concerns. One of the long-term impacts of recent damage due to Helene, is the potential spread of invasive plants in the landscape. Invasive plants are more likely to gain a foothold in our area if there is exposed ground, and events such as recent flooding and wind damage can spread these plants throughout the landscape. The negative impacts are easy to see, including displacement of native species in the ecosystem at large, and displacing desired plants in the garden. Hurricane Helene drastically altered the landscape and eroded streambanks, fields, and yards while also depositing soil that can contain invasive plant seeds resulting in an increase in distribution and spread of the invasive plant population. It is important now more than ever to know which invasive plants to keep your eye out for, and what you can do to manage these invasive plants to prevent their establishment in your landscape, and in our community at large. Coming up with a IPM plan (Integrated Pest Management plan) will be critical to holistically address this threat to our area.
Erosion and Open Canopy: Aftermath of Helene
Exposed ground due to erosion from flooding, or fallen trees/other vegetation can be an opening that invasive plants take advantage of. If you have ground that has been newly exposed, cover crops or selectively choosing those plants that naturally fill in those spaces, will be critical in preventing invasive plant establishment. There are special considerations for stream bank erosion which can be found here, and you can also utilize the cover crop selector tool as well to determine what options you might have. Native grass establishment with fescue blends can be conducted in the fall. You can also monitor the site and know which plants are invasive and selectively pruning/removing out problematic invasive plants while cultivating native vegetation. Regardless, identification of invasive plants is critical in stopping establishment in our community as a whole.
Importance of Monitoring:
So how do you know what to look for in invasive plants? Begin to look for plant characteristics such as leaf orientation, plant habit, and flowers/fruit that might form to properly identify potentially invasive plants. Over the next few months, I will be posting invasive plant BOLO’s and management strategy factsheets to address some of the invasive plant threats. You can visit the NC Invasive Plant Council list for WNC for a list of invasive species that are a threat in the mountains. If you have any questions about invasive plant identification, please reach out to your local NC Cooperative extension office and we would be happy to assist you.
Now that I know what it is, what are my control options?
Once you have been able to identify the invasive species, what management strategies exist to prevent invasive plant spread? There are three main forms of control that we will discuss today that should be considered in your invasive plant management gameplan:
Cultural Control: Maintaining healthy plant establishment and desirable ground cover is the best way to prevent establishment of invasive plants. For newly eroded areas, we have discussed the impact cover crops can have already, but also consider mulching or encouraging native successional plants to cover the ground thereby preventing opportunities for invasive plant establishment. By limiting the opportunities for invasive plants to establish themselves from the get-go, we set ourselves up in the long run to prevent them from becoming an entrenched issue.
Mechanical Control:It is important to know the biology of the plant in question. When does the invasive plant flower and set seeds? When is the optimum time to control a particular invasive plant? These questions can be answered often times by looking a the biology of the plant itself. Plants can be more susceptible to specific treatments at certain times of their life cycle. Some plants are more susceptible to herbicide foliar treatment if they are actively growing, and flush cuts can be a viable method to generate susceptible growth to foliar herbicide treatment for certain invasive plants.
Knowing how a plant spreads can also inform us of strategies that we have in our arsenal to prevent spread to begin with. For example, when looking at Japanese stiltgrass, it is a prolific seeder (if left to flower, it can produce up to 50,000 seeds per square foot). If we know that it sets seeds by the end of August, then mowing before seed set could be a strategy to prevent overall spread to other areas while coupling that with an herbicide spray to better penetrate the newly cut stiltgrass in question. Window cutting is another example of a great mechanical strategy against woody invasive vines on trees. The idea is to cut off water and food to the above ground portions of the plant. This is often paired with painting an herbicide on the bottom portion of the vine to kill the root system. See the photo below:
