Oriental bittersweet is an invasive plant that should be avoided by all gardeners, and everyone else for that matter. It is a deciduous twining vine with glossy leaves and small greenish flowers. It also produces attractive orange berries that are prized in fall decorations.
I have to confess that before I knew about the plant's nasty habits, I sometimes bought sprays of the berries to decorate my front door. But I will not do this ever again as the vine can strangle shrubs and small trees and weaken larger trees by girdling the trunks and weighing down the crowns.
Another invasive species is the glossy buckthorn that grows as a tall shrub or small tree. It has red-purple berry-like fruit. Both the glossy and common buckthorns occur in a variety of habitats and spread rapidly through natural areas by seed. They take over the understory and eliminate the diverse plants that occur naturally and sustain our native wildlife.
Alternative plants that can be used instead of the aforementioned invasive species are the lance-leaf and Carolina buckthorn, serviceberry and native dogwoods.
Another invasive plant to avoid is the biennial herb known as garlic mustard that is threatening large areas of this country. Other thugs are reed canary grass, common reed grass and the autumn olive, which can grow as either a shrub or small tree.