Frangula alnus
| Glossy Buckthorn | |
|---|---|
| File:Glossy buckthorn.jpg | |
| Scientific classification | |
| Kingdom: | |
| Division: | |
| Class: | |
| Order: | |
| Family: | |
| Genus: | |
| Subgenus: | Frangula
|
| Species: | R. frangula
|
| Binomial name | |
| Rhamnus frangula | |
| Synonyms | |
|
Frangula alnus P. Mill | |
Rhamnus frangula (commonly referred to as Glossy Buckthorn, Alder Buckthorn, Breaking Buckthorn and Black Dogwood) is a tall deciduous shrub native to Europe, North Africa, and Asia. It is an invasive species in North America, invading forests in the Northeastern and wetlands and moist forest in the Midwestern United States,[1][2] and is expected to continue to expand its North American range with time.[3]
Description
Rhamnus frangula is a tall deciduous shrub, sometimes referred to as a small tree, that grows up to 6 m (20 ft) tall and 4.5 m (15 ft) wide. Leaves are ovate, 4-5’’ long by 3-4’’ wide, arranged oppositely or whorled on stem. The flowers are small, greenish-white, hermaphroditic, and insect pollinated, flowering in mid-June in New Hampshire.[4] Fruit is small black berries that drop in late summer to early fall. Individual plants can produce as many as 400-1800 fruits with three seeds each. Seeds are dispersed by birds and mice, but many seeds simply fall to the ground underneath the parent, creating a dense local population.
Habitat
Rhamnus frangula grows well in sunlight and moderate shade, but less vigorously in dense shade.[1] It is highly adaptable and pollution tolerant.[4] In the Northeastern United States, where it is an invasive species, it invades forests and grows in the understory in spots with a lot of light.
Distribution
Rhamnus frangula is native to Europe, North Africa, and Asia. It is an invasive species in North America, especially in the Northeastern United States.[1] It was likely introduced to North America 200 years ago, and became naturalized in Canada about 100 years ago. In North America, it was once planted for hedgerows, forestry plantings, and wildlife habitat.[3]
Invasion of Forests
In the Northeastern and Midwestern United States, where it is an invasive species, R. frangula invades forests and grows in the understory in spots with a lot of light. These areas, usually where a tree has fallen, normally allow seedlings to grow and eventually fill in the gap in the canopy. But when R. fragula invades and grows in these locations, its dense canopy prevents light from reaching the ground and therefore prevents the seedlings from growing.[4]
Because lower topographical areas with moist, fertile soil tend to favor R. frangula, it tends be grow more densely with larger individuals in these areas, and is very problematic for land managers. Uplands forests are not invaded as easily as lower lying ones. Hemlock-oak stands, which tend to be older stands of trees, are much less suitable for R. frangula because the density of the tree canopy creates a more shady environment that is not as suitable for R. frangula. Eastern White Pine stands are easily invaded because they allow more light to reach the forest floor, and tree stands that are cut are very quickly invaded while undisturbed stands are rarely invaded.[5]
Control
Small R. frangula saplings can be hand-pulled, but control of larger examples is best achieved using herbicides.[6] R. frangula and the related species, common buckthorn (Rhamnus cathartica), have been banned from sale, transport, or import to Minnesota[7] and Illinois.[8] Glossy buckthorn is considered invasive, but not banned, in Connecticut.[9]
Folklore
Galen, a Greek physician of the second century A.D., knew of alder buckthorn, although he did not distinguish, clearly, in his writings between it and other closely related species. All of these plants though, were credited with the power to protect against witchcraft, demons, poisons, and headaches.
Medicinal Purposes
The more mundane, but true value of of the plant is its bark as a Laxative, and it was not until the 1300's that alder buckthorn was used for that purpose. Buckthorn bark's laxative action is relatively gentle, and it may not have been considered powerful enough to be worthy of attention in a day when violent purges were in fashion.
Other Uses
Alder buckthorn wood was formerly used for Shoe lasts, nails, and veneer. its charcoal was prized by makers of gunpowder. The bark yields a yellow dye, and the unripe berries furnish a green dye.
References
- ^ a b c "Common Buckthorn and Glossy Buckthorn". University of Maine Cooperative Extension Bulletin #2505.
- ^ "glossy buckthorn". Invasive.org: Center for Invasive Species and Ecosystem Health.
- ^ a b Wingard, Hanna S. "Invasion of transition hardwood forests by exotic Rhamnus frangula: Chronology and site requirements". University of New Hampshire, 2007.
- ^ a b c "Guide to invasive upland plant species in New Hampshire" (PDF). New Hampshire Department of Agriculture, Markets & Food Terrestrial Invasive Plant Species, page 14.
- ^ Chelsea Cunard and Thomas D. Lee. "Is patience a virtue? Succession, light, and the death of invasive glossy buckthorn ( Frangula alnus)". Biological Invasions:Volume 11, Number 3 / March, 2009.
- ^ "What you can do to control buckthorn!". MN Department of Natural Resources.
- ^ "Buckthorn". MN Department of Natural Resources.
- ^ "Reminder to Gardeners: Some Exotic Plants Banned in Illinois". Illinois DIllinois Department of Natural Resources. April 22, 2004.
- ^ "Connecticut Invasive Plant List July 2009" (PDF). CT Invasive Plants Council.
