Plums are a diverse group of species. The commercially important plum trees are medium-sized, usually pruned to 5–6 metres (16–20 ft) height. The tree is of medium hardiness. Without pruning, the trees can reach 12 metres (39 ft) in height and spread across 10 metres (33 ft). They blossom in different months in different parts of the world; for example, in about January in Taiwan and early April in the United Kingdom

Source: Wikipedia