Look at the tree's flowers. Malus trees have white, pink or red flowers that have a darker bud. Flowers will emerge in April or May before the foliage does.
Look at the tree's fruit. The apple can be bright red, yellow or green. They mature in clusters and are mature and ready for picking in September or October.
Look at the tree's trunk. Malus trees have a gray, brown or reddish-brown bark. The bark on young trees is smooth while older trees have knotty bark.
Look at the tree's leaf color. Malus trees have leaves that are medium to dark green. Some types of Malus trees will have reddish-purple leaves that may turn yellow in the summer.
Look at the tree's leaf shape. Malus trees have serrated edges.