Rhamnus cathartica Seeds | Common Buckthorn

Dense clusters of black buckthorn berries among glossy serrated leaves on a spiny twig — Common Buckthorn (*Rhamnus cathartica*): Rhamnaceae, Europe and western Asia.

LATIN NAME: Rhamnus cathartica

COMMON NAME: Common Buckthorn

Plant Profile

Common buckthorn is a spiny, deciduous shrub or small tree of five to eight metres, with glossy, finely toothed leaves, tiny green flowers in spring and black berries in dense clusters in autumn. It is native to hedgerows and scrub across Europe and western Asia, and it is one of the most aggressive woody invaders of North American woodland, where it leafs out early, holds its leaves late and shades out the spring flora. It is also the winter host of the soybean aphid. The twigs end in a thorn, and the buds are dark and pressed close to the stem, which is how it is told from the native buckthorns.

Science & Biotechnology

The species is dioecious, so only female plants carry the berries, and the fruit contains emodin and other anthraquinones that make it a violent purgative; the specific name says as much. The berries also yield sap green, a pigment much used in watercolour and in manuscript illumination, and the bark gives a yellow dye. In North America the shrub is a serious invader, and its role as the overwintering host of Aphis glycines, the soybean aphid, has made it a target of agricultural control programmes. Removal is difficult because the seed bank persists for years and the stumps coppice. Its leaves are also a food plant for the larvae of several moths, including the brimstone.

Uses & Benefits

Its uses are historical: the berries as a purgative under professional supervision, the fruit as a dye, the wood as charcoal and the shrub as hedge and cover. None of that outweighs its behaviour in the places where it is not native. In Europe it is a legitimate hedgerow plant for wildlife and a good source of autumn colour in a wild corner, and it should be planted there and not elsewhere. The berries are poisonous to people in any quantity, and children are the usual casualties, since the fruit looks like a sloe. The wood is also dense enough for small turnery, and the charcoal was once valued by gunpowder makers.

Growing from Seed

Sow the seed in autumn and leave the pots outside; it needs cold and damp, and germination may be spread over two springs. The seed is hard-coated, so scarification helps. Grow the seedling in any soil, in sun or shade, and plant out at two years, remembering that only female plants fruit. If it is to be grown at all, keep it in its native range, and cut and treat stumps rather than letting it spread, because it layers and suckers. Birds carry the seed far, so a fruiting hedge is a commitment. It also tolerates both drought and flooding, which is part of why it is so hard to dislodge.

Our Take

A hedgerow native with a dye in its berries and a purgative in its chemistry, and an invasive elsewhere. Grow it only where it belongs, and never where soybeans are grown.

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