White mulberry is a medium-sized tree with a short trunk, broad, round crown, and many fine twigs.
Leaves are alternate, simple, 2–6 inches long, with 0–5 lobes, coarse teeth, pointed tip. Three main veins arise from the base. Undersurface smooth, paler than above. Bleeds milky sap. Leaf stalk smooth.
Bark is thin, brown, sometimes tinged with red or yellow, with shallow grooves and long, narrow ridges; it ages to resemble elm bark.
Twigs are reddish-brown, smooth to slightly hairy, turning gray and smooth with age. Bleed milky sap.
Flowers April–May, with male and female flowers on the same tree or on different trees. Male catkins ½–1½ inches long; female catkins ½–¾ inch long.
Fruits June–August, blackberry-like; white to pink to purple; globe-shaped to oval; ½–¾ inch long.
Similar species: Our native red mulberry (M. rubra) has leaves hairy underneath, more often lobeless, with hairy leaf stalk; its fruits are cylindrical and start out red (not white or pink); its catkins and leaves are larger. Another species, the black mulberry (M. nigra) grows in the Old World; most people think it has the best-tasting berries, which you might find in preserves or dried at international groceries.