Glossy buckthorn (Frangula alnus)
Hand pull: Any time of year when the ground is soft, especially after a rain, hand pull small plants by the base of the stem. Be sure to pull up the entire root system. Hang from a branch to prevent re-rooting. For larger plants, use a Weed Wrench™. Continue to monitor the area every year for new seedlings.
Cut stump: Cut plants back any time of year. Wrap a few layers of burlap or thick plastic over the stump and tie tightly with twine. You will need to check stumps periodically and cut back any new growth.
Propane torch: This method can be effective on seedlings. For more information, check out this summary of mechanical treatment options from the University of New Hampshire.
Cut stump: Cut the plant 4 inches above the ground. Use a drip bottle to apply a 18-21% glyphosate solution to the stump within one hour of cutting. This is best done in late summer through winter when plants are transporting resources to their root systems.
Low volume foliar spray: This method is used for dense populations and best left to a contractor. In the fall, when native plants are losing their leaves, spray a 2% glyphosate or triclopyr solution on the entire leaf surface of the plant. In order to avoid drift to native plants, spray only on calm days.
"Glossy buckthorn is a large shrub or small tree that can grow to heights of 30 ft. (9.1 m). The dark green leaves are shiny, alternate (sometime opposite) and simple with prominent venation. The flowers are inconspicuous, pale yellow in color and occur in clusters in the leaf axis. Flowering occurs in the spring. The fleshy fruit ripens to a dark purple color. The bark is gray to brown with white lenticels. It invades moist woodlands and disturbed areas throughout the Northeast and Midwest. Its rapid growth and prolific seed production make this plant an aggressive invader that can form dense thickets which shade and displace native understory plants, shrubs, and tree seedlings." (source: http://www.invasive.org/browse/subinfo.cfm?sub=5649)
Buckthorns reproduce by seed but plants can root sprout or regenerate even after they are cut or burned. Plants mature at 5-6 years old. Seed production is prolific. Common buckthorn fruits ripen from August to September while glossy buckthorn fruits ripen earlier—July to August. Seed germination rates are high and germinate well in the shade. Seeds remain viable for at least 2 years.
Class B Noxious Weed
- Birds and mammals feed on buckthorn berries during the winter, aiding in the dispersal of seeds. While buckthorn may benefit from this behavior, the feeding animals do not. Buckthorn berries contain emodin, a natural laxative, that prevents mammals from digesting sugars found in the berries, like this Eastern chipmunk shown above.
- Like many other invasive trees and shrubs, buckthorn leafs out early and retains its leaves into late fall, giving it a much longer advantageous growing season than native plants.
- Buckthorn can increase the amount of nitrogen in the soil, impacting the composition of native species that can grow in the area.