Culture
Easily grown in fertile, well-drained soils in full sun. Tolerates light shade. Tolerates a wide variety of soils. Also tolerates heat, humidity, drought and urban pollution. Prune in late fall or early winter when fully dormant to avoid bleeding. This is a weedy, fast-growing tree or large shrub that spreads, often aggressively, by root suckers and/or self-seeding. Wildlife feeds on the fruits and spreads the seed. Invasive tendencies (particularly for fruit-bearing female trees) have resulted in placement of this tree on restricted tree lists for the States of Tennessee, South Carolina, Georgia and Florida. Trees are best sited in locations protected from strong winds (shallow root systems make trees vulnerable to toppling over).
Noteworthy Characteristics
Broussonetia papyrifera, commonly known as paper mulberry, is a fast growing deciduous tree or large shrub. It mature to 40-50’ tall with a broad rounded crown in the wild, but usually grows much shorter in cultivation. Native to Japan, China and Polynesia. It was originally introduced into the U.S. as a rapid-growing shade tree. Over time, it has escaped cultivation and naturalized in a number of areas in the eastern U.S. from New York to Missouri south to Florida and Texas. In optimum conditions, paper mulberry will easily spread to form thickets or colonies in waste areas, fields, forest margins and roadsides. Paper mulberry is dioecious (separate male and female trees). Young twigs are downy reddish-brown. Gray bark matures over time to gray brown with furrows. Trees have a milky sap. Large, broad-oval, dull green leaves (to 8” long) with serrate margins and asymmetrically cordate bases are rough-textured above and dense-tomentose beneath. Variable leaf shapes range from lobed to mitten shaped, sometimes with deep irregular sinuses. Leaves are alternate, sometimes opposite, or sometimes whorled along the stem. Yellow-green fall color can be interesting. Pale green flowers bloom in April and May (male in pendulous catkins to 3” long and female in rounded flower heads). If pollinated, flowers on female trees give way to reddish purple to orange aggregate fruits in balls.
Genus name honors Pierre Auguste Marie Broussonet (1761-1807), French physician, naturalist and one-time professor of botany at Le Jardin des Plantes de Montpellier.
Specific epithet comes from the Egyptian word papyrus meaning paper and the Latin word ferre meaning to bear in reference to the use of tree bark to make paper.
Common name comes from a long-time use of the tree bark in eastern Asia to make paper and from the use of inner tree bark in Polynesia to make barkcloth (Tapa cloth).
Problems
No serious insect or disease problems. Canker, leaf spot and root rot may be troublesome.
Uses
Male trees can be effective shade or street trees because they will not spread by self-seeding or drop messy fruit. Female trees can spread invasively into areas where they will crowd out native plants.