Appearance
Morus alba is a small, 30-50 ft. (9.1-15.2 m) tall, deciduous tree that invades disturbed areas throughout the United States.

Foliage
The alternate leaves are polymorphic (variably shaped), 2-8 in. (5.1-20.3 cm) long and shiny with blunt teeth and heart-shaped bases. Young bark, the bark along the roots, and the inner bark along the trunk are often bright orange in color. Older bark is gray with narrow, irregular fissures.

Flowers
Flowering occurs in April. Plants are normally dioecious (male and female flowers on separate plants). Male flowers are small, green and occur in 1-2 in. (2.5-5.1 cm) long catkins. Female flowers are inconspicuous and crowded in short spikes.

Fruit
Fruits are multiple-seeded berries. They can range in color from black to pink or even white when ripe.

Ecological Threat
Morus alba is very similar to the native red mulberry (Morus rubra), but may be distinguished by the leaves. Morus alba leaves have glossy surfaces whereas the leaves of Morus rubra do not. Morus alba is found throughout the United States, where it invades old fields, urban lots, roadsides, forest edges, and other disturbed areas. It poses an ecological threat by displacing native species, possibly hybridizing with and transmitting a root disease to the native Morus rubra. Morus alba is native to Asia and was introduced in colonial times as a food source for silkworms.

Resources

• Weed of the Week - USDA Forest Service
• Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service

Selected Images

Maps

Invasive Listing Sources

• Alachua County Cogongrass Initiative
• City of Ann Arbor Michigan Parks and Recreation
• Georgia Exotic Pest Plant Council - Category 3
• Hoffman, R. & K. Kearns, Eds. 1997. Wisconsin manual of control recommendations for ecologically invasive plants. Wisconsin Dept. Natural Resources, Bureau of Endangered Resources. Madison, Wisconsin. 102pp.
• Indiana Invasive Species Council - Invasive Plant List
• Indiana Terrestrial Plant Rule
• Invasive Plant Association of Wisconsin
• Invasive Plant Species of West Virginia
• Iowa Forest Invasive Plants
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• John Randall, The Nature Conservancy, Survey of TNC Preserves, 1995.
• Kentucky Exotic Pest Plant Council - Significant Threat
• Maine Invasive Plants
• Maryland Cooperative Extension Service.  2003. Invasive Plant Control in Maryland. Home and Garden Information Center, Home and Garden Mimeo HG88. 4 pp.
• Maryland Department of Natural Resources Policy: Restriction on Planting Exotic Invasive Plants
• Maryland Invasive Species Council - Invasive Species of Concern in Maryland
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• Non-Native Invasive Plants of Arlington County, Virginia
• Non-Native Invasive Plants of the City of Alexandria, Virginia
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ohio Invasive Species Council
• Ontario’s Invading Species Awareness Program Tracked Species List
• Pennsylvania Department of Conservation and Natural Resources Invasive Plants
• Plant Invaders of Mid-Atlantic Natural Areas
• Rhode Island Natural History Survey
• South Carolina Invasive Pest Council
• Virginia Invasive Plant Species List
• WeedUS - Database of Plants Invading Natural Areas in the United States
• West Virginia Native Plant Society, Flora West Virginia Project, and West Virginia Curatorial Database System, September 3, 1999
• Wisconsin Noxious Weeds
• Wisconsin's Invasive species rule – NR 40

References