WHO KNEW the Week of Feb 24 is Invasive Species Week!
Several invasive plant species, such as Japanese barberry, glossy buckthorn and Japanese bittersweet infest our woodlands and roadsides. They multiply quickly and choke out native vegetation. Some were deliberately introduced as abundant producers of fruit for wild birds.
Plants that are invasive here are well behaved in their native homes, where insects and animals have evolved to eat the foliage and keep the plants in check. For example, garlic mustard forms only small patches in its native Europe, where 69 kinds of insect are known to prey on it. Yet garlic mustard can carpet swaths of forest here, where it has no predators. Wildlife disappears along with the native vegetation it had depended on, a clear loss of biodiversity.
Only a few of the thousands of kinds of non-native plants that have been introduced turn out to be both suited to local growing conditions and immune to local predators. But these few can spread mercilessly. Japanese knotweed is practically uncontrollable except by herbicide and garlic mustard poisons the soil for other kinds of plants.
On the other side of the balance between plants and predators are invasive insects that arrive without enemies (usually bacteria or other insects). One is the emerald ash borer, which is now attacking ash trees in Hanover. Another is hemlock woolly adelgid, which has affected hemlocks near the Canaan end of Goose Pond Road.
Ash and hemlock have been wiped out in places where these newcomer insects have become fully established. Fortunately, some insects that help control them in their original home territories have been identified. After a long period of testing to make sure these potential saviors won't harm beneficial species that belong here, they have been released in the wild. It remains to be seen whether this defense succeeds.
What can you do?
- Learn to recognize and then remove invasive plants and insects - especially ones in waterbodies and forests
- Volunteer to help with restoration work by removing the invaders in your neighborhood
- Help your neighbors with ID and control
- Share information about the invasives
For more information:
- UNH information about some of these plants and pests
- National Invasive Species Awareness Week (NISAW) is February 24—28, 2025
- UNH Program (on-line only) “Nature in Your Backyard: Identifying Common Trees and Upland Invasive Plants” April 9, 2025 | 12:00 - 1:30pm Online only