Flowering crabapples are ornamental trees that comprise more than 35 species and 700 varieties. Flowering crabapples bloom in springtime with pink blossoms, each of which has five petals and up to 20 yellow stamens. Crabapples often begin blooming before the leaves even unfurl in the spring. Flowering crabapple trees range in height from 6 feet to 50 feet. Crabapples can be spreading, weeping, pyramidal or vase-like, depending on the species and particular cultivar.
Water your flowering crabapple trees deeply to soak the soil around the root zone. Water once a week during the first year after planting them. After the trees are established, water the flowering crabapples only during droughts and prolonged dry spells, watering deeply once every two or three weeks to provide at least 2 inches of water.
Feed your flowering crabapples with 5 lbs. of 20-5-10 NPK (Nitrogen-Phosphorous-Potassium) fertilizer, spread over the entire root zone. Apply 10 lbs. of 20-5-10 NPK fertilizer for crabapple trees with larger canopies that measure 30 feet by 30 feet or more. Feed your flowering crabapples only when the leaves grow small or pale and the tree is growing less than 5 to 6 inches per year.
Prune your flowering crabapple trees each year in spring, before early June, to remove all dead, diseased, damaged, crossing or crowded branches. Also remove all suckers growing from the roots or trunk base and water sprouts growing from the branches.
Keep an eye out for insects invading your flowering crabapple trees, especially caterpillars, leafhoppers, Japanese beetles, leaf rollers and leaf miners. Treat your infested crabapple trees with an appropriate insecticide, according to the directions on the label.
Watch out for fire blight, a bacterium that causes the branches and twigs to blacken and can kill the crabapple tree. Control fire blight by removing and destroying all infected twigs and branches.