Despite flurries of snow, it’s not too late to get outside to conquer invasive weeds. While native and naturalized plants are shutting down for the winter, a few invasive species are still green and growing strong. The ability to grow when other plants are dormant is a competitive advantage to invasive weeds, as there is little competition for resources. But, this also means that Buckthorn seedlings and shrubs are easier to find and destroy as they’re the probably the only green under your trees.
Buckthorn is an invasive under-story shrub that was once used for hedges in landscaping. What once made this shrub attractive for hedges turns out to be bad for forests, as it can form dense thickets that crowd out native plants. These thickets not only prevent other shrubs and herbaceous natives from thriving, but prevent the new growth of forest trees, which in turns changes the composition of forest plants and wildlife. Furthermore, these plants not only degrade wildlife, but serve as a host to nuisance diseases and pests such as crown rust fungus and soybean aphid.
There are two types of Bucktorn, the Common Buckthorn (Rhamnus cathartica) and Glossy Buckthorn (Frangula alnus). Common buckthorns do well in woodlands, savannas, fields, and roadsides. They have egg-shaped, dark green leaves that are dull to glossy, and are easily confused with dogwoods, plums, and cherries. The shrubs produce round, berry-like fruits arranged in clusters that persist through out the winter. Common Buckthorn is the easiest to spot in the fall, as leaves stay green the longest. Glossy Buckthorn does best in wet areas, though will also grow in dry areas. The leaves are oval, smooth and dark green with a glossy sheen and fall color. These shrubs can be easily confused with native chokecherry. Like common buckthorn, they produce round berries, but the berries do not persist. As both types are easily confused with native species, make sure to positively identify any shrubs before removal. Guidelines, such the Minnesota DNR Buckthorn Control pamplet, are quite helpful with identification features.
If you have Buckthorn, there are several steps you can take to reduce and remove populations. When raking leaves, remove any seedlings manually or with herbicide. If you have established thickets, several options are available. Check out more information on Management of Invasive Plants in Wisconsin – Buckthorn for control options.