Black Mulberry
Morus nigra
The Black Mulberry (Morus nigra) is a small, long-lived deciduous tree revered since antiquity for producing what many consider the finest-tasting of all mulberry fruits — large, intensely sweet, dark purple-black berries with a complex, wine-like flavor that has been prized by Persian, Greek, Roman, and European civilizations for thousands of years. Unlike its cousin the White Mulberry, the Black Mulberry was cultivated not for silkworms but for its superb fruit.
• Considered the most flavorful of all mulberry species — the fruit is larger, sweeter, and more intensely aromatic than White or Red Mulberry
• Among the longest-lived fruit trees, with specimens known to survive and produce fruit for 300 to 500 years
• The species epithet "nigra" means "black," referring to the dark purple-black color of the ripe fruit
• Mentioned by the ancient Greek physician Dioscorides (c. 40–90 CE) in "De Materia Medica" as a medicinal and culinary fruit
• The fruit has inspired poetry and literature for millennia, including references in Shakespeare's works
Taxonomy
• Thought to originate in the area of present-day Iran (ancient Persia), Armenia, the Caucasus Mountains, and surrounding regions of western Asia
• Exact native range is uncertain due to millennia of cultivation and naturalization across the Mediterranean, Europe, and western Asia
• Introduced to Europe in ancient times — the Romans spread its cultivation throughout the Mediterranean, and it was well-established in Greece and Italy by the 1st century CE
• First described by Carl Linnaeus in 1753 in Species Plantarum
• Widely planted across southern and central Europe since Roman times, particularly in Spain, Italy, France, and England
• In England, Black Mulberry was popularized in the 16th and 17th centuries, and many ancient specimens survive in London parks and old gardens
• The "Mulberry Tree" mentioned in Shakespeare's works (he had a famous Black Mulberry in his Stratford-upon-Avon garden) was likely this species
• Less widely cultivated globally than the White Mulberry due to its more restricted climate requirements
• The genus Morus has a complex taxonomy, with Black Mulberry distinguished from other species by its chromosome number (2n = 308, the highest in the genus), large dark fruit, and hairy leaves
Trunk and Bark:
• Typically reaches 6 to 10 meters (occasionally up to 15 meters) in height with a trunk diameter of 30 to 60 cm
• Bark orange-brown to grayish-brown, becoming deeply furrowed and ridged with age, developing a rugged, picturesque character in old specimens
• Often develops a gnarled, spreading habit with multiple stems
Crown:
• Dense, rounded to spreading, often with a somewhat irregular, picturesque silhouette
• Branches spreading to drooping, with stout twigs
Leaves:
• Broadly ovate to cordate, 8 to 20 cm long and 6 to 15 cm wide
• Base deeply cordate (heart-shaped), margins irregularly toothed, upper surface rough and scabrous (sandpapery), lower surface softly hairy (pubescent)
• Dark green above, paler and grayish-green beneath
• Usually unlobed (unlike White Mulberry, which frequently has lobed leaves)
• Turn yellow in autumn before falling
Flowers:
• Monoecious — both male and female flowers on the same tree
• Male catkins: cylindrical, 2 to 4 cm long, greenish-yellow
• Female catkins: short, ovoid, greenish
• Wind-pollinated in late spring
Fruit:
• Multiple fruit (syncarp), ovoid to cylindrical, 2 to 3 cm long and 1.5 to 2.5 cm wide
• Dark purple to nearly black when fully ripe, with a glossy surface
• Extremely juicy, sweet, and richly flavored with a distinctive tart-sweet, wine-like complexity
• Staining — the dark juice permanently dyes fingers, clothing, and surfaces a deep purple
• Ripens over an extended period in summer, requiring multiple harvests
• More cold-hardy than often assumed — tolerates winter temperatures to -20°C, though it fruits best in warm temperate climates with long, hot summers
• Prefers deep, fertile, moist but well-drained soils and does not tolerate waterlogging or drought as well as White Mulberry
• The rough, hairy leaves are less palatable to silkworms than the smooth leaves of White Mulberry, which explains why this species was not adopted for sericulture
• Fruits are consumed and dispersed by a wide variety of birds including blackbirds, thrushes, starlings, and pigeons
• Dense canopy provides excellent shade and nesting habitat for birds
• Relatively pest-free compared to many fruit trees, though mulberry canker and bacterial blight can affect older specimens
• Ancient trees often develop hollow trunks while continuing to produce abundant fruit — a testament to the species' exceptional longevity
• In the Mediterranean, Black Mulberry is a characteristic element of traditional agricultural landscapes and old gardens
• Fruit production peaks in trees 20 to 50 years old but continues at reduced levels for centuries
• Listed as Least Concern on the IUCN Red List
• However, the species has declined in commercial importance as White Mulberry and mulberry hybrids have become preferred for large-scale fruit production
• Ancient Black Mulberry specimens in Europe are living heritage — many trees in England, France, and Italy are 200 to 500 years old and represent irreplaceable genetic resources
• Conservation of old-growth Black Mulberry trees in historic gardens and monasteries is important for preserving genetic diversity
• The species is maintained in germplasm collections at several European and Asian agricultural research institutions
• Efforts to revive Black Mulberry cultivation are underway in parts of Turkey, Iran, and the Mediterranean for premium fresh fruit and preserves
Fun Fact
According to legend, King James I of England imported Black Mulberry trees in the early 1600s to start an English silk industry, not realizing that silkworms prefer White Mulberry leaves. The enterprise failed spectacularly — but the Black Mulberry trees thrived and spread across England, and many ancient specimens still growing in London parks today are believed to be from James's original importation.
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