Prunus spinosa Seeds | Blackthorn

Blackthorn (Prunus spinosa) in early spring, white flowers on bare spiny branches — Blackthorn (*Prunus spinosa*): Rosaceae, the spiny hedge shrub of Europe, source of sloes and one of the first spring blossoms.

LATIN NAME: Prunus spinosa

COMMON NAME: Blackthorn

Plant Profile

Blackthorn is a dense, spiny shrub of the rose family, three to five metres tall, with blackish bark, small toothed leaves and a habit of suckering into impenetrable thicket. The flowers open in March and April, before any leaf, so the bare black branches carry a dusting of white for a fortnight.

It is native across Europe and into western Asia, and it is one of the defining plants of the old hedgerow: laid into a hedge, its spines make a stock-proof barrier that will last decades. The fruit, the sloe, is a small, blue-black drupe with an astringent, mouth-drying flesh.

Science & Biotechnology

Prunus spinosa is a diploid and one of the parents of the cultivated plum, P. domestica, which arose through hybridisation with P. cerasifera. The genus is prone to such events, and the blackthorn’s contribution to plum ancestry has been confirmed by both cytology and DNA markers.

The seed is notoriously difficult. It has a thick, impermeable stone and a dormant embryo, so germination in the wild may take two winters. Research on the species has concentrated on breaking that dormancy for nursery production, with warm stratification followed by cold giving the most reliable results. In hedgerow surveys the species is one of the shrubs that most reliably marks an old boundary.

Uses & Benefits

Sloes are too astringent to eat raw, but steeping them in gin with sugar produces a liqueur that has been made in Britain for at least three centuries. The fruit also goes into jams, syrups and country wines, and the bark was once used for a dark dye.

In the landscape its value is ecological. A blackthorn hedge flowers when bees have little else, shelters nesting birds in its spines, and holds stock and soil on a bank. The wood is hard and close-grained and is used for walking sticks and small turnery, and it once made a charcoal valued by gunpowder mills.

Growing from Seed

Stratify the stones warm first: eight to ten weeks at twenty degrees, then twelve weeks at three degrees. Sow them in a nursery bed rather than a pot, since the seedling resents transplanting, and expect some stones to wait a second year before showing.

Grow the seedlings on for two years, then plant them at thirty to forty-five centimetres apart for a hedge, cutting them back hard after planting to encourage branching from the base. For a specimen shrub, leave it alone and let the thicket form. It tolerates any soil except the wettest. Water new plants through their first summer, then leave them alone.

Our Take

The best stock-proof hedge in Europe, and a fruit that needs gin to be appreciated. Grow it for the bees and the birds, and make the sloe gin anyway. Plant it where the thorns can do some good, and pick the fruit after the first hard frost. Wear gloves when you do it.

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