(Morus alba)

Photo 29: B. Navez, France

Biology

• a small tree growing to 15 metres (50 ft) in height
• belongs to the Mulberry family
• leaves are oval-shaped and often have deep lobes (making them look mitten- or glove-shaped)
• undersides of the leaves have whitish hairs on the veins
• produces berry-like fruits that may be white, pink, purple, or nearly black
• birds eat the berries and may be responsible for much of the spread of White Mulberry since the seeds within the fruit pass through the bird without damage

Photo 30: Chuck Bargeron, University of Georgia

History in Canada

• introduced to North America in the late-1800's from Asia for its edible fruit and to provide leaves for the silkworm industry
• occurs in southern Ontario
• available from nurseries

Impact on Trees

• closely related to the native, endangered Red Mulberry (Morus rubra) whose only Canadian occurrence is southern Ontario
• at most Ontario locations of Red Mulberry, White Mulberry is hybridizing with the native tree
• such hybridization could eliminate the endangered Red Mulberry by 'genetic swamping'

Control

• cutting trunks followed by herbicide application to the cut trunks
• herbicide application to the entire tree if small
• several years of control may be needed since the seeds are unaffected by the above methods and seedlings can recolonize an area

Links

• Trees of Wisconsin, Cofrin Centre for Biodiversity, University of Wisconsin-Green Bay. (http://www.uwgb.edu/biodiversity/herbarium/trees/moralb01.htm)
• Plant Population and Evolution Research Laboratory. University of Guelph. (http://www.uoguelph.ca/botany/research/evollab/mrubrainfo.htm)
• Wikipedia, the free encyclopedia. (http://en.wikipedia.org/wiki/Morus_alba)
• Canadian Wildlife Service, Environment Canada. Invasive Plants of Natural Habitats in Canada (http://www.cws-scf.ec.gc.ca/publications/inv/14_e.cfm#targ38)
• Plant Invaders of Mid-Atlantic Natural Areas (Web Version). Swearingen, J., K. Reshetiloff, B. Slattery, and S. Zwicker. 2002. Available as a PDF file from: (http://www.nps.gov/plants/alien/pubs/midatlantic/index.htm)
• Canadian Botanical Conservation Network. Invasive Tree Species. (http://www.rbg.ca/cbcn/en/projects/invasives/i_tree2.html)
• Asymmetrical introgression between two Morus species (M. alba, M. rubra) that differ in abundance. K. S. Burgess, M. Morgan, L. Deverno and B. C. Husband. 2005. Molecular Ecology 14:3471-3483. Article available as PDF file from: (http://jade.botany.utoronto.ca/ResearchLabs/BarrettLab/pdf/Burgess%20et%20al.%202005.pdf)