Prunus apricots, of cherries, and of plums, all of which have cultivars developed for commercial fruit and nut production. The almond is not a true nut, the edible part is the seed. Other species are occasionally cultivated or used for their seed and fruit. A number of species, hybrids, and cultivars are grown as ornamental plants, usually for their profusion of flowers, sometimes for ornamental foliage and shape, and occasionally for their bark. The Tree of 40 Fruit has forty varieties grafted on to one rootstock. Species such as blackthorn ("Prunus spinosa"), are grown for hedging, game cover, and other utilitarian
Prunus simonii is particularly aromatic, much more so than "Prunus salicina", with a comparatively high level of hexyl acetate, which gives apples their aroma. Plant breeder Luther Burbank devoted a lot of work to hybridizing this species with the Japanese plum ("Prunus salicina") and developed a number of cultivars from the hybrid. Of these, the cultivar 'Climax' was particularly notable for its importance to the fruit shipping industry of California. Other influential plum cultivars that Burbank developed with "P. simonii" ancestry include 'Maynard', 'Chalco', 'Santa Rosa', and 'Formosa'. Those two species and the European species "Prunus cerasifera" have contributed the majority of