Sloes are the small fruits of the blackthorn tree which is often used in hedging. It's sharp, spiky branches forming a dense thicket. Many British hedgerows have thorney plants such as hawthorn, blackberry or roses. The small white flowers bloom in March and the sloes ripen in October. Sloes have a bluish-black colour and a soft bloom on their skins. They are far too astringent to eat, but they make the most delicious fruit liqueur.