Morus rubra, commonly known as the Red Mulberry, is a species of mulberry native to eastern North America, from Ontario and Vermont south to southern Florida and west to southeast South Dakota and central Texas. Although common in the United States, it is listed as an endangered species in Canada.
Red Mulberry is a deciduous tree, growing to 10-15 m tall, rarely 20 m, with a trunk up to 50 cm diameter. The leaves are alternate, 7-14 cm long and 6-12 cm broad, simple, broadly cordate, with a shallow notch at the base, typically unlobed on mature trees although often with 2-3 lobes, particularly on young trees, and with a finely serrated margin. The upper surface of the leaves is noticeably rough, similar in texture to fine sandpaper, and unlike the lustrous upper surface of the leaves of White Mulberry (M. alba). The underside of the leaves is covered with soft hairs. The leaf petiole exudes milky sap when severed. Red Mulberry is hardy to subzero temperatures, relatively hardy to drought, pollution, and poor soil, though the White Mulberry is hardier.
The flowers are relatively inconspicuous: small, yellowish green or reddish green, and opening as leaves emerge. Male and female flowers are usually on separate trees although they may occur on the same tree.
The first English colonists to explore eastern Virginia in 1607 mentioned the abundance of both mulberry trees and their fruit, which was eaten, sometimes boiled, by the native Powhatan tribes. It remains a widely used fruit in pies, tarts, cobblers, as well as eaten raw in a similar fashion as blackberries.
- Flora of North America: Morus rubra
- Ambrose, J. D., & Kirk, D. (2004). National Recovery Strategy for Red Mulberry (Morus rubra L.). Ontario Ministry of Natural Resources, Guelph, Ontario, Canada
- Farrar, J.L. (1995). Trees in Canada. Fitzhenry and Whiteside/Canadian Forest Service, Markham, Ontario.
- Trees of Alabama and the Southeast: Red Mulberry, Morus rubra, Moraceae.
- California Rare Fruit Growers
- Burgess, K. S., Morgan, M., Deverno, L., & Husband, B. C. (2005). Asymmetrical introgression between two Morus species (M. alba, M. rubra) that differ in abundance. Molec. Ecol. 14: 3471–3483 pdf file.