Juniper is found on well-drained rocks and soils and tolerates extremes of climate and pH. In Scotland, it occurs on cold, wet acid sites and grows amongst heather and whinberries. In the south of England it is found on hot, dry chalky hillsides. The largest southern population of juniper in England is inside the Ministry of Defence's Establishment at Porton Down in Wiltshire. Here there are estimated to be over 14,000 bushes. It is thought that many of these date from the introduction of myxomatosis and the reduction of the rabbit population, which led to reduced grazing of the seedlings.