At our recent Community Plant Swap, the Master Gardeners supported native plant selections and discouraged attendees from picking up those few "invasive" plants that were found in circulation. Valid advice though it is, why should we choose native, non-invasive plants for planting and avoid exotic invasives? Even further, what should we do when we find ourselves dealing with a garden (or yard!) take-over? Read on for expert information regarding invasive exotic species, how to identify them and what the best way to control their growth.
What is an invasive exotic species?
Invasive exotic plants are ones that have been introduced by people from other continents or ecosystems, whose introduction causes economic or environmental harm, or harm to human health.
How did they get here?
Many were brought here intentionally for ornamental use, erosion control, or wildlife habitat. Others were brought accidentally or as byproducts of human industry; in transporting goods in the hulls of ships, by carried seeds.
How do invasive exotic species take over?
They have a lack of natural enemies to control their populations, because when they are brought to a new ecosystem, their predators don’t come along. They can also be spread by prolific seeding, which is when they are dispersed inadvertently by animals and humans. Some invasive species can even spread by stolons or rhizomes underground, making the roots hard to remove. Most of them green out early, which shades out native plants and improves their own chance of survival. Deer also play a role in the spread of invasive species by only browsing on native plants, preventing them from growing.
Why do we care?
After the loss of habitat through development, the encroachment of invasive exotic plants causes the most harm to our native species. Development is something we are always going to be doing, while the spread of invasives is something we can prevent. These invasive weeds crowd out native plants that are important to the ecosystem. Our native animals suffer when the native plants they depend on are no longer around. Getting rid of these non native plants will improve forest quality by allowing the native plants to grow, which provide food and shelter for wildlife. Healthy ecosystems also help provide clean air and water for people, as well as filter the soil. A forest may look healthy with lots of older native trees, but invasives in the understory will eventually affect the overstory by preventing new trees from growing.
What can we do?
Learn how to identify and remove invasive species by reading the Weekly Weed articles and becoming a Weed Warrior! Most counties have one of these programs to do invasive species control and keep their forests healthy. The Carroll County Weed Warrior program was initiated by a Master Gardener, Carolyn Puckett, in 2010. Anyone can be a Weed Warrior! There are currently over 400 volunteers in our database who have removed over 40 acres of invasive plants. We work mainly at Bear Branch and Piney Run Park, but are always looking for new places to work and new groups to network with. You can help change the forest from being covered with invasives, to providing food and shelter for wildlife! Contact firstname.lastname@example.org for more information.