The best known mulberry species are the red (Morus rubra), native to the eastern United States; the white (Morus alba), native to eastern and central China and the black (Morus nigra), native to western Asia. All are part of the Moraceae family, as are figs. The deciduous trees are distinguished by their lobed, alternate leaves and abundant, edible fruits. The white mulberry was named for the color of its buds, rather than the color of the fruit, which can be white, pinkish-white, purple or nearly black.
The white mulberry is the host plant for the silkworm, and it has been essential to the Chinese silk industry for at least 4,000 years. The plant is naturalized in Europe and arrived in the United States in the 1700s, when colonists attempted to establish a domestic silk industry. The silk industry failed, but the white mulberry succeeded in the United States, becoming weedy and invasive in some places. In the 20th century, Luther Burbank developed a white mulberry with larger than normal amounts of foliage to help increase silk production worldwide.
The juicy fruits of the mulberry can be used in much the same ways as other berries--in jams, jellies, syrups, juice and wine. Hybrid varieties may have larger, better-tasting fruit than species mulberries, which are sweet but without complex flavor. Black mulberries are reputed to have the best flavor.
Birds and other animals love mulberries and play in important role in spreading the seeds enclosed in the fruits. The trees do not attract pollinating insects, as the flowers are either wind pollinated or self pollinating. Grown en masse, mulberries can form an effective windbreak.
Mulberries are survivors; they are tough, adaptable trees that can tolerate drought, salt spray and urban pollution. They will also regrow from the stumps of felled specimens. The largest red mulberries can reach 70 feet tall, while black mulberries may only reach 30 feet. The tallest white mulberries can reach 50 feet. Dwarf hybrid varieties are commercially available and are more suitable for smaller spaces. Mulberries grow in USDA Hardiness Zones 7 to 9.
Forms and Varieties
Some mulberries have a shrubby, multi-stemmed form. There are also weeping forms of the white mulberry and a species, Morus bombycis, that has a form with contorted branches. Some nurseries offer Morus alba varieties with attractively twisted or cut leaves, enhancing their landscape value.
The biggest headache for property owners with mulberry bushes is the purple fruit, which stains fabrics, walkways and carpets. To avoid this problem, select varieties that have white or light colored berries. Another option is to plant dark-fruited specimens away from high-traffic areas.