Glossy Buckthorn is a deciduous shrub or small tree easily identifiable by its thornless branches and stems, which are covered by fine, wooly brown hairs. The leaves are simple, dark green and shiny on top. It prefers moist soils and tolerates sun, but thrives in shade.  It is commonly found in disturbed places like roadsides and fields.  Glossy buckthorn has insignificant yellow-green flowers at leaf axils in spring. followed by dark purple berries in summer and fall. The bark is dark gray or brown with white lenticels.

Common buckthorn (Rhamnus frangula), also invasive, is a similar species but the outer bark is dark gray and the inner bark is orange. 

Pulling by hand or via a weed wrench is an effective method of control for seedlings and smaller plants.  Regular mowing where possible will reduce or halt fruiting. Successive cuttings twice a season for at least 3 years, will reduce the size and density of infestations but will likely not eradicate it. Larger stems may be girdled and re-sprouts clipped as they emerge.

Smooth Alder, or Hazel Alder (Alnus serrulata) can be confused with glossy buckthorn, but the leaves have a rough, toothed margin instead of a smooth. Also, throughout much of the year, smooth alder holds soft cones, or catkins, which are very different from the juicy berries of glossy buckthorn.

To learn more about it, and to see additional photographs go to Lower Hudson PRISM as well as PennState Extension.