by Leah Allen
The word invasive means to spread prolifically, undesirably, and/or harmfully. And that’s exactly what some non-native plant species have done throughout our land. This time of the year, invasive plant species are more obvious to the eye, especially along our highways, roads, open fields, and forests. All those heavy vines strangling trees that you see are invasive plant species, brought to the US in the 1800’s from other countries as ornamental plants to help build our growing landscape. Unfortunately, they’ve spread their seeds far and wide and have naturalized over much of our terrain wrapping themselves around trees, smothering vegetation, monopolizing nutrients, and becoming a serious threat to our native environments.
Oriental bittersweet, Celastrus orbiculatus, also known as Asiatic Bittersweet, is one of the most familiar invasive plant species that can be seen around town and much of the eastern US. For those of you who are unsure of it, maybe you’ve seen the red berries with a yellow shell on a twirling vine used for decorating around Thanksgiving? That’s Oriental bittersweet and as festive as it looks, it’s horrendous, to put it mildly. This woody vine is native to Eastern Asia and can aggressively climb up neighboring trees and shrubs or any other vertical structure they can find. As it grows, the bittersweet literally chokes out the host tree or plant it’s clinging to. It also reproduces quickly by spreading strong orange underground roots The seeds of Bittersweet are eaten and dispersed by birds and other mammals helping to spread this nuisance of a plant even more.
There are no biological controls for Oriental Bittersweet, meaning there are virtually no noted predators or diseases feeding on this plant to decrease its growth, development, and spread. Manual, mechanical, and chemical control methods are all effective in removing and or at best controlling this noxious plant. Using a combination of all the methods often brings the best results. The entire plant needs to be removed including their root systems. For vines, make a cut using loppers or a bow saw, four feet from ground level separating top growth from the crown and roots.This will cut off life and kill the upper portion. Never pull vines from the trees as the very structure and canopy of the tree is compromised by the heavy vines!! Finally, the cut-and-paint method is a chemical control using a herbicide painted on by a brush after a fresh cut is made. For further detail and instruction on how to remove Oriental Bittersweet, visit www.cipwg.uconn.edu
Japanese Barberry, Berberis thunbergii, is another invasive plant that can be found around North Stonington, thriving in full sun to full shade, wetlands. full canopy forests, and fields alike. This woody plant native to Asia is covered in spiny thorns growing 3-6’ tall and wide forming dense humid thickets, making it an ideal habitat for mice seeking protection from predators. Many gardeners may not be aware of the link between Japanese Barberry and Lyme disease, especially when they’re being sold a drought tolerant, shade tolerant, low maintenance shrub at the nursery. A multi-year study conducted by researchers in Connecticut has concluded that the larger number of Japanese Barberry, the higher the incidence of Lyme carrying ticks. Black legged ticks and deer ticks feed on the mice that inhabits this invasive plant. Japanese Barberry can spread like swaths crowding out all native plant species causing collateral damage to native ecosystems.
In addition to the fore-mentioned invasives, others you may see around town include Japanese honeysuckle, Japanese knotweed, Multiflora Rose (wild roses), and winged Euonymous. For a full list of Connecticut invasive plant species and other information, visit www.cipwg.uconn.edu
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