Alder, Buckthorn

Description

Rhamnus frangula

Alder buckthorn is a non-spiny deciduous shrub, growing to 3–6 m (10–20 ft), occasionally to 7 m (23 ft) tall. The bark is dark blackish-brown, with bright lemon-yellow inner bark exposed if cut. The shoots are dark brown, the winter buds without bud scales, protected only by the densely hairy outer leaves.

Unlike other “buckthorns”, alder buckthorn does not have thorns. The flowers are small star-shaped with five greenish-white acute triangular petals, hermaphroditic, and insect-pollinated, flowering in May to June in clusters of two to ten in the leaf axils. The fruit is a small black berry, ripening from green through red in late summer to dark purple or black in early autumn, containing two or three pale brown seeds. The seeds are primarily dispersed by frugivorous birds, which readily eat the fruit.

Alder buckthorn grows in wet soils in open woods, scrub, hedgerows and bogs, thriving well in sunlight and moderate shade, but less vigorously in dense shade; it prefers acidic soils though will also grow on neutral soils.

Alder buckthorn is used to make gunpowder, pigments and dyes. It’s a beloved plant of the brimstone butterfly.