Fruit

Blackthorn

Prunus spinosa L. · sloe, sloes · Polish: Śliwa tarnina

Edible with care

Photo: MurielBendel / Wikimedia Commons, CC BY-SA 4.0

How to identify it

Dense shrub with strong, long thorns (modified short shoots).
White flowers appear in abundance before the leaves open (April–May).
Small, round, blue-black fruits with a bluish bloom.
Fruits very astringent — practically inedible when fresh.

Where it grows

Scrub, field margins, woodland edges and roadsides, on almost all soils — sandy, clayey and stony.

In the kitchen and the home medicine cabinet

Fruits for processing are picked ripe, from October; after frosts or freezing they are less astringent. Tarninówka (sloe nalewka), preserves, kompot, wines, juices; in the past the fruits were pickled. The flowers are dried at about 35 °C.

Caution The seeds (stones) contain amygdalin — a cyanogenic glycoside from which toxic hydrogen cyanide is formed; do not eat the stones and do not crush them when making preserves. Fruits that have frozen on the bush spoil quickly — process them straight away. Poisonings from sloes have been recorded around the world.