Description:
Columnar buckthorn (Frangula alnus) Weed.
Plant habit:
A tall shrub or small tree, buckthorn can grow 20 to 25 feet tall and up to 10 inches in diameter. A columnar variety of glossy buckthorn has also been developed.
Bark:
Brown or gray in color, often with scattered short, horizontal, light-colored lines called lenticels. Older bark of common buckthorn can be rough, and strips of bark may curl. Inner bark (sapwood) is a distinctive orange/yellow color (expose inner bark by scraping with a knife, key, or fingernail or by nicking tough specimens with a chainsaw).
Branches:
Buds and leaves are mostly opposite in common buckthorn mostly alternate in glossy buckthorn. Common buckthorn often has short, sharp, spike-like thorns at the tips of twigs. Glossy buckthorn is thornless; twigs are tipped with buds.
Leaves:
Leaves are oval, dark green, glossy, and sometimes pointed at the tip. Common buckthorn leaves are hairless, have 3-5 pairs of veins curving toward the tip from the mid-vein, and have tiny teeth along the margins. Glossy buckthorn leaves sometimes have fine hairs on the underside, lack teeth on the margins, and have 8-9 pairs of veins that run parallel from the midrib. Leaves appear early in the spring and stay green late into fall, well-beyond the growing season of most native woody plants.
Habitat:
Common buckthorn occurs in uplands, mainly in the understory of oak woods, savannas, riparian woods but also in grasslands. It is often found in disturbed areas such as thickets, hedgerows, pastures, abandoned fields, roadsides and on rocky sites. Glossy buckthorn is an aggressive invader of wet or moist soils, but also grows well in a wide variety of upland habitats, including old fields, roadsides and dry woodlands. It has become a problem in wetlands as varied as acidic bogs, calcareous fens and sedge meadows. It is capable of growing in both full sun and shaded habitats.
Management:
Life History and Invasive Behaviour:
Both buckthorns are characterized by prolific reproduction via seed, tolerance of a wide variety of habitats and high levels of growth-form variability (physical traits vary
Columnar buckthorn (Frangula alnus) Distribution in North America shown in green.
due to local environmental conditions). In full sun, buckthorn can produce fruit a few years after establishment, and seeds remain viable in the soil for many years. Fruit production may be delayed for 10 to 20 years in shaded habitats. Once established, buckthorn has the ability to spread aggressively in nearly any habitat. Seedlings establish best in high light conditions but seeds also germinate and grow in the shade. The vigor of buckthorn germination and growth is directly related to light availability. Once plants begin to produce seed, buckthorn can rapidly form dense thickets. Birds eat the abundant fruits and facilitate the long-distance dispersal of seeds. The fruits act as a laxative to the digestive system, aiding in dispersal. Typical of other non-native understory shrubs, buckthorn leaves emerge early in spring, shading out native wildflowers. This shading can also prevent the establishment of tree seedlings. Buckthorns aggressively monopolize light, nutrients and water, effectively outcompeting most plants that attempt to grow beneath them. In the fall, common buckthorn leaves remain green long after most native trees and shrubs have lost their leaves; infestations are easy to spot as winter approaches. As buckthorns devastate native plant communities, habitat may be rendered inhospitable to most wildlife.
Impacts on Forestry and Foresters:
On Forestry: Both species aggressively compete with local woody and herbaceous flora. Because of its dense, shady growth and early leaf-out, buckthorn discourages germination and survival of desirable tree species. Nitrogen-rich leaf litter produced by buckthorn rapidly decomposes and doesn’t support fire—in contrast to many of the species it displaces—decreasing management options.
On Foresters: Common buckthorn can form dense, sharp-thorned thickets that hamper access to forests and interfere with forestry operations.
Sourced From: na.fs.fed.us/spfo/invasiveplants/…/common-and-glossy-buckthorn.pd..
