Crab Apples are beautiful ornamental trees which produce a variety of small sour frut.  Their blossoms in Spring are prolific.    Crab apple (Malus) bonsai thrive in full sun and require significant watering, especially when fruiting. They need annual or biennial repotting in early spring and careful pruning. Protect them from hard frosts during winter dormancy and monitor for pests like aphids and powdery mildew