White mulberry

White mulberry (Morus alba) has escaped cultivation and has naturalized throughout the United States, often overtaking areas and outcompeting native mulberry populations. Its fruit is edible for humans and tastes sweet, usually ripening around the 4th of July in Minnesota.

White mulberry is often misidentified as red mulberry, a rare but native tree in Minnesota. White and red mulberry can cross-pollinate, resulting in a hybrid species. The Minnesota Department of Natural Resources provides identification details for red mulberry (Morus rubra).

For management information, see Controlling unwanted trees and shrubs.

How to identify white mulberry

White mulberry is a medium-sized tree, reaching 30 to 50 feet tall at maturity with an equal crown spread. 

Stem

• Twigs are smooth and range from red to orange-brown, with raised pores.
• As the tree matures, the trunk bark turns grey to brown and forms ridges and furrows.
• Twigs bleed a milky sap when cut.

Leaves

• Alternate, simple leaves are 2 to 6 inches long with a glossy surface and toothed edges.
• The leaf shapes will vary even on the same tree:
  • They can be unlobed or irregularly lobed, with 2 to 7 lobes.
  • Most are round, except for the terminal lobe, which is pointed.
  • Mitten shape is common.
• Leaves bleed a milky sap when cut.
• Leaves turn yellow in the fall.

Flowers

• Male and female flowers occur on separate plants, but occasionally, both genders of flowers will be produced on the same tree.
• Flowers in drooping catkins, green to yellow in color, bloom in spring.

Fruits and seeds

• Fruit resembles elongated blackberries and varies in color from white to pink to deep purple, measuring from 1/2 to 1-1/2 inches in length.
• Fruits from June to August; they usually ripen and are best eaten in July.
• Birds also love the fruit.

Author: Hana Kim, Extension educator