Though A. rubrum is usually easy to identify, it is highly changeable in morphological characteristics. It is a medium to large sized tree, reaching heights of 27 to 38 metres (90 to 120 ft) and exceptionally over 41 metres (135 feet) in the southern Appalachians where conditions favor it's growth. The leaves are usually 9 to 11 centimetres (31⁄2 to 41⁄4 in) long on a full grown tree.