Hawthorn is a shrub or small tree growing 1-4 m tall. Its leathery leaves (3-8 cm long) have sharply toothed margins, particularly in the upper half. Its white or pinkish flowers (10-15 mm across) are arranged in dense clusters at the tips of the branches. These flowers have five petals (5-9 mm long and 4-5 mm wide) and numerous stamens. Its rounded fruit (5-10 mm across) turn from green to bluish-black or purplish-black in colour as they mature.