White Mulberry

Morus alba is native to northern and central China, where it has been cultivated for millennia.

• Believed native to a broad area of northern and central China, possibly extending into Korea and Japan
• Cultivated across China for over 5,000 years for silkworm culture, making it one of the oldest cultivated trees
• Now widely naturalized and planted throughout temperate and subtropical regions of Asia, Europe, North America, South America, Africa, and Australia
• Introduced to Europe in the 12th century and to North America in the 1600s in early (and largely unsuccessful) attempts to establish a colonial silk industry
• First described by Carl Linnaeus in 1753 in Species Plantarum
• The species epithet "alba" means "white," referring to the white fruits of some cultivated varieties (though fruit color ranges from white to pink, red, purple, and nearly black)
• The genus Morus comprises approximately 10 to 16 species distributed across temperate and subtropical regions of the Northern Hemisphere and parts of Africa
• Mulberry leaves were so valuable in ancient China that they were sometimes used as currency, and the area of mulberry plantations was a measure of a region's wealth
• The Byzantine Empire smuggled silkworm eggs out of China in the 6th century CE, establishing a European silk industry and spreading White Mulberry cultivation westward

Morus alba is a medium-sized, fast-growing, deciduous tree.

Trunk and Bark:
• Typically reaches 10 to 20 meters in height with a trunk diameter of 30 to 80 cm
• Bark yellowish-brown to grayish-brown, becoming deeply furrowed and ridged with age, with irregular plates
• Young twigs are slender, greenish-brown, smooth or slightly pubescent

Crown:
• Rounded to broadly spreading, often wider than tall
• Branches spreading to drooping, creating a dense canopy of variable density

Leaves:
• Highly variable in shape — ovate, cordate, or deeply lobed (often on the same tree), 6 to 20 cm long and 5 to 15 cm wide
• Base cordate (heart-shaped), margins irregularly toothed or serrate
• Bright green, glossy above, paler and slightly hairy beneath
• Leaves are the primary food of silkworms — their nutritional quality (protein content, moisture, and leaf texture) directly determines silk quality
• Variable leaf shape is an adaptation to different light conditions — lobed leaves in sun, unlobed in shade

Flowers:
• Monoecious or dioecious — trees may bear both male and female flowers or only one sex
• Male (staminate) catkins: cylindrical, pendulous, 1 to 3 cm long, yellowish-green, shedding pollen in spring
• Female (pistillate) catkins: short, ovoid, greenish, developing into the compound fruit

Fruit:
• Multiple fruit (syncarp), cylindrical to ovoid, 1 to 3 cm long
• Color highly variable: white, pinkish, red, dark purple, or nearly black depending on cultivar
• Sweet, mildly tart, juicy, composed of many tiny fused drupelets
• Ripens in late spring to early summer
• Highly perishable — fruits last only 1 to 2 days after picking

Morus alba is a highly adaptable species with significant ecological roles.

• A pioneer species in its native range, colonizing disturbed sites, forest edges, and riparian zones
• Leaves support an enormous diversity of insects, most notably the domesticated silkworm (Bombyx mori) and numerous wild silk moth species
• Fruits are an important food source for birds, particularly robins, cedar waxwings, starlings, and tanagers, which disperse seeds widely
• Deer, raccoons, opossums, and foxes also consume fallen fruits
• Highly adaptable to different soil types including clay, loam, and sandy soils, with tolerance for moderate salinity and alkalinity
• Drought-tolerant once established, though fruit production benefits from consistent moisture
• Can become invasive in some regions — particularly in the eastern United States, where it hybridizes with the native Red Mulberry (M. rubra), threatening the native species' genetic integrity
• Fast growth rate of 60 to 120 cm per year in favorable conditions
• Relatively short-lived for a tree — typically 50 to 75 years, though some specimens reach 150 years
• Shallow but wide-spreading root system helps stabilize soils on slopes and banks

White Mulberry is widespread and not considered threatened.

• Listed as Least Concern on the IUCN Red List due to its vast cultivated and naturalized range
• The species is one of the most widely planted trees in the world for silkworm culture, fruit production, and ornamental use
• Genetic diversity in native Chinese populations is a conservation priority, as wild germplasm may contain valuable traits for silkworm feed quality and disease resistance
• In North America, White Mulberry is considered an invasive species in many eastern states, where it displaces the native Red Mulberry (Morus rubra) through competition and hybridization
• The native Red Mulberry is listed as Endangered in several US states and is threatened by genetic swamping from White Mulberry
• Conservation efforts for Morus alba focus on maintaining diverse germplasm collections in China, Japan, and international gene banks