- Name also: Black Dogwood, Glossy Buckthorn, Columnar Buckthorn, Breaking Buckthorn, European Alder, Fen Buckthorn
- Latin synonym: Frangula dodonei, Rhamnus frangula
- Family: Buckthorn Family – Rhamnaceae
- Growing form and height: Shrub or smallish, multi-stemmed tree. 2–6 m (7–20 ft.).
- Flower: Regular (actinomorphic), small. Sepals five, greenish, triangular. Petals broad, white to greenish, with rounded tip. Pistil formed from five fused carpels. Stamens five, filaments short. Inflorescences 2–6-flowered axillary cymes.
- Leaves: Alternate. Stalked, medium-sized, entire, hairless. Stalk brown-hairy. Blade obovate, deep green above, glossy.
- Buds: Scaleless, brown, densely haired.
- Fruit: Shiny drupe, green at first, later red, black when fully ripe.
- Habitat: Rich waterside spruce swamps, mire margins, shores, forest margins, roadside scrub.
- Flowering time: June–July.
Buckthorns (Rhamnus) are shrubs or smallish trees. The genus comprises more than 100 species most of which are native to East Asia. More than ten are native in Europe, most of them in the Mediterranean countries.
Alder buckthorn is a sparsely branched shrub or small tree which prefers fairly damp and rich sites. In Northern Finland it is quite demanding. Berries and bark of alder buckthorn are poisonous. This plant has been used in dyeing e.g. wool. Bark yields for yellow, berries for greenish colours.