The red mulberry is a small tree, rarely 50 feet high and 2 feet in diameter, often found growing in the shade of larger trees. This tree is quite urban-tolerant. The leaves are alternate, rounded, or somewhat heart-shaped. Leaves are usually undivided with coarsely toothed margins. Some of the leaves, especially on young trees and thrifty shoots, are mitten-shaped or variously lobed.
Terminal buds are absent.
Stems exude milky sap when cut. The bark is rather thin, dark, and grayish-brown and peels off in long, narrow flakes. May flowers are small and greenish. The flowers are of two kinds on the same or different trees and borne in long, drooping catkins. Female catkins are shorter and appear with the leaves.