Culture
Best grown in medium moisture, well-drained, acidic loams in full sun. Adapts to a wide range of soils. Established trees have some drought tolerance. Although some flowers may be lost, it is best to prune this tree as needed in late winter. Spring pruning should be avoided as it produces fresh, open cuts where fireblight bacterium can enter.
Noteworthy Characteristics
Malus is a genus of about 35 species of deciduous trees and shrubs from Europe, Asia and North America.
Genus name from Latin is an ancient name for apple.
‘Ralph Shay’ is a rounded, horizontally-branched, medium-sized, white-flowered crabapple tree that typically matures to 15-20’ tall with a slightly wider spread. Single white flowers bloom in spring (April in St. Louis). Flowers are followed by bright red crabapples (to 1 1/4” diameter) that mature in fall and persist well into winter. Birds are attracted to the fruit. Fruits (large for crabapples) are a good selection for making jellies or preserves. Ovate dark green leaves (to 3” long) produce little fall color. Parents are M. 'Wolf River' x M. x zumi var. calocarpa. Cultivar name honors Purdue University plant physiologist Ralph Shay (1918-1980). Simpson Orchard Company Nursery 1976.
Problems
The main diseases of crabapple are scab, fire blight, rusts, leaf spot and powdery mildew. Potential insect pests are of lesser concern and include tent caterpillars, aphids, Japanese beetles, borers and scale. Spider mites may occur.
‘Ralph Shay’ has slight susceptibility to apple scab. Generally good disease resistance to the other main diseases of crabapples.
Uses
Plant as a specimen/accent or in small groups. General landscape use.
Street tree.