Sweet Sour 1. Botanical description A. Sweet cherry. Leaves are relatively large, elliptic with acute tips, petioled, and strongly veined. Bloom occurs relatively late in spring, so frost is less of a hazard than for other stone fruits, except sour cherries, which bloom slightly later. Pollination is absolutely essential for production, since sweet cherries are self-incompatible.
Bees are the main pollinator.
Pollinizers are usually set every third tree in every third row, or in alternate rows. Thinning is unnecessary for fruit size development, and since a high proportion of flowers must set for a crop, this is not practiced. B. Sour cherry. Medium sized tree with a rounder, more spreading habit than the erect sweet cherry. Leaves elliptic with acute tips, smaller than sweet cherry, petioled.