Glossy buckthorn (Rhamnus frangula), non-native to the United States and Canada, was brought to North America in the 1800s. The glossy buckthorn is invasive in nature, growing in such a manner that it crowds out native shrubs and vegetation. Identifying glossy buckthorn in the spring, summer and fall--when it possesses leaves, flowers and fruits--is a bit easier than recognizing it in the winter, when it lacks these features.
To be able to identify glossy buckthorn, you need to know where it most often grows. Glossy buckthorn is a naturalized plant in parts of the Northeast and in the northern central sections of the United States. Glossy buckthorn occurs also in the wild in eastern parts of Canada. The shrub, or small tree, will invade ecosystems such as bogs, swamps, fens and meadows that are typically damp. It can also thrive in upland sites such as the edges of woodlands, abandoned farm fields, and along the sides of the road.
Size and Form
When seeking glossy buckthorn in the winter, it is best to concentrate your efforts on tall shrubs in the range of 10 to 18 feet high, although some can be as tall as 20 to 25 feet. Two cultivars of glossy buckthorn exist, with one being the 10 to 12-foot tall 'Columnaris' hybrid, which is narrow in form. The branches on this type of glossy buckthorn start low down on the trunk. 'Aspenifolia' is another hybrid, growing to be from 6 to 10 feet in height. Glossy buckthorn forms dense thickets, with the shrubs all tending to be about the same size. The shrub form will have multiple stems emanating from its base, while the tree from can have a trunk with a diameter of as large as 10 inches.
Buds and Twigs
The Wisconsin Department of Natural Resources notes that the buds that develop on the ends of the twigs appear "naked" and "hairy." These features give the glossy buckthorn a look that can help identify it even in winter. The twigs have a curved form and the leaf scars that emerge after the leaves fall off form noticeable bumps. The silhouette of the twigs will reflect this shape.
If you take a small section of branch from a glossy buckthorn and cut it open, you will see that the sapwood is yellow. Beneath this layer of wood lies the heartwood of glossy buckthorn. This section will be shades of pink and/or orange.
The bark of the glossy buckthorn ranges from grayish to hues of brown, states the Pennsylvania Department of Conservation and Natural Resources. The bark has small horizontal lines on it known as lenticels that are lighter in appearance than the surrounding bark. These often give the bark a somewhat speckled facade.