Crab apple trees are similar to apple trees, only they have much smaller fruit. Also, unlike apples, crab apples are usually left on the tree for birds to eat and not harvested. However, they still make a lovely yard tree. They offer a plethora of flowers in the spring. Then in the fall, they bear colorful fruit as the leaves change. Crab apple trees are hardy to Zone 4. Crab apple tree care is similar to apple tree care, except that crab apple trees are less fussy.
Plant crab apple trees in full sun. They also need well-drained loamy soil in which to thrive. If your soil is too sandy or clay-like, add compost or manure and work it into a depth of about 4 feet to improve your soil. You can plant crab apple trees in either the spring or the fall, although a bare root crab apple should be planted in the spring.
Water your crab apple tree well while it is under a year old. Water it once a week in the spring and summer for 10 minutes each watering. Water it once a month in the fall and winter for 10 minutes a watering. Once the crab apple tree is more than a year old, it will need little additional watering. Water it twice a month if the weather is very dry. Water for 10 minutes each watering.
Prune your crab apple tree every spring after the tree has stopped blooming. Cut off any dead, damaged or diseased branches at the base of the tree. Also, remove any water sprouts or suckers at the base. Crossing branches should also be removed to allow light into the inner branches.
Fertilize your crab apple tree once it is 2 years old if it is not growing well. Use a mixture of 20-5-10 applied at the base of the tree. Apply 2 lbs. of fertilizer while the tree is under 4 years old. Once the tree is older than 4, apply 3 lbs. of fertilizer. Fertilize your crab apple tree every spring before it blooms.