Apple trees are part of the Rosaceae family of plants. Apple trees are deciduous evergreens and are one of the most commonly cultivated fruit trees in the world. Different species of apple trees produce different varieties of leaves. Learning to identify the leaves of an apple tree can help you to determine which type of apples the tree will produce, or help you make a decision about what kind of apple tree you want in your yard.
Find the similarities. All apple tree leaves have three features in common: they are deciduous, grow in an alternate fashion on the branches and have toothed margins. If the leaves have these properties, then they might be apple tree leaves.
Examine the leaf's color. All apple tree leaves are bright to dark green on the upper surface, and a duller silver-grayish green on the lower surface. Some apple tree leaves, like those of the sweet crab apple tree, are a yellow-green, while those of a prairie crab apple tree are a shiny green with a subtler hue of green underneath. Check to see if the leaves in question have some sort of two-tone green color, lighter on top and duller on the underside.
Notice the leaf's shape and size. Apple trees have simple leaves, meaning the leaf is one solitary blade. While most apple tree leaves are an oval shape, some variations due exist. The Baltimore crab apple tree, for example, has triangle-shaped leaves, while the Southern crab apple tree has oblong-shaped leaves, earning its nickname, "narrow-leaf crab apple." The leaves are small, averaging 1.5 to 3 inches long, with the exception of a few crab apple varieties that have leaves reaching upwards of 4 inches long.
Examine the leaf's texture and size. Most apple tree varieties have at least one side coated in small hairs. Crab apple trees have this feature on both sides of the leaf. In addition, most apple tree leaf stems are also coated in a fine layer of hair.
Photograph the leaves for comparison. With a digital camera or a camera phone, take a picture of a small leaf cluster and place the sample in a small sandwich bag.
Use an online plant identification manual, or one from a store, and compare the photograph to apple tree leaf examples in the guide. Pay attention to the shape, size, color, structure and texture.