Common Buckthorn
(Rhamnus cathartica)
Overview
Native to Europe, Common Buckthorn was introduced to North America as an ornamental shrub for fencerows and wildlife habitat. Because of its tolerance of a wide range of moisture and light conditions, along with its prolific seed production, buckthorn is able to successfully invade many habitats. Buckthorn grows throughout Ontario in a variety of habitats, and is often found in woodlands and open fields.
Main Threats
Buckthorn forms dense thickets, with the shade produced by these dense stands reducing local biodiversity, often resulting in a monoculture. It is one of the first trees to leaf in the spring, giving it a head start over competing species. It has been speculated that this shrub also produces a substance that inhibits the growth and development of other understory plant species, thus ensuring its success.
Identification
Photo: Nature Conservancy of Canada
Leaves
Buckthorn is fairly easy to identify depending on the time of year, as it leafs out early in the spring and is one of the last deciduous shrubs to lose its leaves in late autumn. The leaves are sharp tipped, and somewhat fine toothed.
Photo: Ontario Invasive Plant Council
Bark
The bark of Buckthorn is dark grey to black, with prominent small horizontal lines.
Photo: North American Native Plant Society
Berries & Thorns
Buckthorn produces clusters of berry-like black fruit starting in August and into the fall. The fruit remain on the stem throughout winter.
As the name suggests, sharp thorns are found along the branch, with most branches ending in a short, sharp thorn.
Additional Resources
The following resources provide more information on Buckthorn, including negative impacts, identification tips, and control methods:
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