I have three crabapple trees that bloomed beautifully in the spring but I’ve noticed that they didn’t leaf out nicely. The leaves seem to be really small. The tree looks sparce. They actually look sickly. I’ve noticed that of other crabapple trees as well. Any thoughts as to what might be wrong.?
There are several diseases that commonly occur on ornamental crabapples every year. These fungal diseases are scab and two Gymnosporangium rusts (cedar-apple rust and cedar-hawthorn rust). A bacterial disease called fire blight is considered to be an occasional problem.
Without a photo and/or additional information ( spots on leaves, colour of leaves) it is difficult to say exactly what is wrong with your crabapple trees.
The following websites provides photos and descriptions of the more common diseases to affect crab apple trees.