Plum

Not widely sold but well worth tracking down for its decent crop of bluish-purple summer fruit. Like all plums, 'Heron' can be grown on different rootstocks depending on what height and shape you want, but the the most common garden kinds are 'Pixy', which produces 1.8-3m (6-10ft) of growth, and 'St Julian A', which gives 3.7-4.5m (12-15ft). Plums can be grown as fans against walls or cordons, or half-standard or standard trees. Since the spring flowers are easily damaged by frost (which adversely affects the crop), throw a fleece over the bush if a frost is predicted.