Mulberries (Morus spp.) are a group of several species of trees native to Asia and North America. The species vary in size and growth habit, but they all are prolific producers of fruits that are desirable to both wildlife and humans.
The red mulberry (Morus rubra) is a native of North America, and it grows widely throughout the eastern United States. It is winter-hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9, and in ideal growing conditions, particularly in the southern United States, it can reach a height of 70 feet. A red mulberry seldom lives longer than 75 years.
The leaves of the red mulberry are toothed along their edges, and they are often deeply lobed. In mid- to late summer, the tree produces berrylike fruits that deepen to a dark red or nearly black color as they ripen.
The white mulberry (Morus alba), a native of China, may grow to 80 feet in height but more typically reaches 30 to 40 feet. It is reliably hardy in USDA zones 4 through 9, and it is somewhat more cold-tolerant than red mulberry. It is a very sturdy tree that tolerates drought, nutrient-deficient soil and urban pollution; its ability to flourish in hospitable conditions gives it a tendency toward weediness in some parts of the United States. White mulberry is very long-lived and may survive for centuries.
The leaves of the white mulberry are smaller than those of the red mulberry and may be lobed or not lobed. White mulberry's fruits are usually lighter in color than those of the red mulberry, although they are often red or dark purple when ripe.
Some cultivars of white mulberry, such as the weeping mulberry (Morus alba 'Pendula') and the contorted mulberry (Morus alba 'Unryu'), have unusual growth habits that make them specimens often favored by gardeners. Both cultivars are hardy in USDA zones 4 through 8.
Black mulberry (Morus nigra) is native to western Asia and is not widely grown in the United States. It less cold-tolerant than red or white mulberry; although it is hardy in USDA zones 5 through 9, it may struggle in climates colder than USDA zone 7. It is also smaller in stature than the other two species, usually reaching a height of about 30 feet. Like white mulberry, black mulberry may live for centuries, though some experts now feel the tree is relatively short-lived.
Black mulberry leaves are similar to those of the red mulberry, and its fruits are large and especially flavorful.
Mulberry trees of all species grow best in full sun and well-drained, but moist, soil. They're generally tolerant of drought, but they may not produce fruits well without adequate water during dry periods.