Frangula alnus

Alder Buckthorn, Glossy Buckthorn
 

Mature Size, Growth, Longevity

A large, multi-stemmed shrub or small, low-branched tree. Gets 10-12' tall and 8-12' wide, rarely to 18' tall. Forms an open, upright-oval outline Medium-fast growth rate.

Native Range

Often grows in wet soils in open woods. Native to Europe, northern Africa, and western Asia. Introduced to North America in the mid-1800's as an ornamental.

Flower and Fruit Details

Perfect, small, 1/8-3/16", creamy-green to greenish-white, star-shaped flowers in May, 2-10 in a cluster in leaf axils of the new growth, not showy, but butterflies and bees are attracted to them, and they are insect-pollinated. The fruit is a berry-like drupe, 1/4-1/3" in size, changing from red to purplish-black, w/ 2 seeds, July-September. Can become invasive as the birds spread the seeds everywhere,

Leaf and Bark Features

Deciduous: Leaves are alternate, simple, 1-4" long and half as wide, oval, obovate or obovate-oblong, entire around the margins, dark green above, lighter green and somewhat pubescent beneath, w/ 8-9 pairs of prominent, impressed veins, & a petiole 1/4-1/2" long. Greenish-yellow or yellow fall color; not outstanding. Young stems slender & pubescent, later glabrous, and marked with prominent, vertical, rectangular, gray lenticels. Older bark is dark blackish-brown, with bright yellow inner bark if cut open.

Culture and Care

Easy to transplant, prefers well-drained soils, but adapts well to various sites and soils, sun to part shade, Somewhat sensitive to soil compaction. Tolerates wet soils, and even bogs. Likes acid to neutral soils. Pollution-tolerant. Zone 3-7. Stem dieback has occurred due to canker or wilt diseases. Extremely cold winters predispose the plant to subsequent fungal canker disease.

Strengths, Weaknesses, Other Facts

3-season interest: Spring, summer and fall. However, this species has become invasive in Kentucky and several northeastern states, and is not recommended. Formerly known as Rhamnus frangula.

Suggested Uses

This species has been determined to be invasive within our local region (KY, OH, and/or IN). Local use is not recommended.
Has been used for hedges and wildlife habitat, but now becoming invasive. The straight-species is of little value for landscape considerations, but the cultivars offer some hope for ornamental qualities.

Taxa and Plants of this Species at BCA

The following taxa are (or were) represented in the collections at Boone County Arboretum. Additional taxa may be available in the trade that are not included here.

  • Frangula alnus 'Asplenifolia' // Glossy Buckthorn, Alder Buckthorn, Fernleaf Buckthorn, Tallhedge Buckthorn
    Tree. Foliage is a bushy, upright-spreading, deciduous shrub with very fine-textured, fernlike, with long, narrow, scalloped, wavy-margined leaves. Grows to 6-12' tall and 6-10' wide. Likes moist to wet soils in full sun to part shade. The 1/4", green fruits change to red, then purplish-black from July to September. Good in shrub border or as a hedge. Yellow to occasional reddish fall foliage color. All parts of the plant should be considered harmful or poisonous to humans if ingested. Nematodes, Japanese beetles, caterpillars, scale and stem cankers could be problems, but usually not serious. Species native to Europe, Western Asia and North Africa. Formerly known as Rhamnus frangula 'Asplenifolia'.
    BT002850b