There are many disease resistant crabs from which gardeners can choose. The following are particularly outstanding.
Indian Summer Crab
Indian Summer is a hybrid of the toringo crab. Hardy to zone three, this round headed tree reaches 18 to 20 feet tall with a matching spread. Opening from red buds, the red blossoms open early to mid season. It has greenish-bronze foliage that turns orange in the fall. The long-lasting fruits are red. It has excellent disease resistance to rust and mildew with good resistance to fire blight and scab.
A variety of the Siberian crab, this rounded tree is hardy to zone three. It reaches 20 to 30 feet in height with an equal spread. Opening from whitish-pink buds, the flowers are white. This is among the earliest of the crab apples to bloom. The foliage brings yellow fall color. This has red to reddish-purple fruits. Jacki crab has excellent disease resistance to rust and scab with good resistance to mildew. It shows some resistance to fire blight.
This broad, weeping tree is shaped like an umbrella. It reaches 15 feet tall with an equal spread. The pink blooms open early to mid season. The gold fruits have a red blush. Louisa has excellent resistance to fire blight and rust, and good resistance to scab.
Madonna crab apple has excellent resistance to the major diseases except for fire blight. This is a dwarf upright tree that reaches 20 feet tall. Opening from white buds, the white blossoms are scented. This tree blooms very early in the season. The fruits are red.
Prairie Fire Crab
Hardy to zone four, this upright to rounded tree reaches 20 feet tall with a matching spread. It has purplish-red to reddish-pink blooms that open late in the season. These open from purplish-red to red buds.
The foliage is initially red, changing to greenish-red. During the fall this can turn orange-red. The fruits are reddish-purple to deep red. Prairie Fire has excellent resistance to fire blight, rust, and mildew. It has good resistance to scab.
Red Jade Crab
Red Jade is a weeping hybrid of the Japanese flowering crab. Recommended for zones three through seven, it reaches 12 feet in height with a spread of up to 20 feet.
This blooms early to mid season. The white blossoms are tinged with pink, while the buds are crimson. The glossy fruits are red. This has fair to excellent resistance to most major diseases, but is susceptible to fire blight.