Japan and Taiwan
Paper mulberry is a deciduous
tree with milky sap that grows to a maximum height of about 45 ft. (15 m.).
The twigs of paper mulberry are hairy reddish brown, the bark is tan and
smooth to moderately furrowed, the wood is soft and brittle, and it has conical
buds. The leaves are densely gray-pubescent, often lobed or mitten-shaped,
and are alternate, opposite or whorled along the stem. The leaf margin is
sharply toothed, the leaf base is heart-shaped to rounded with pointed tips,
and the upper leaf surface is rough feeling. Separate male and female flowers
appear in the spring. Male flower clusters are elongate, pendulous, 2 ½ to
3 in. (6-8 cm) long, and composed of many individual flowers. Female flowers
are globular and about 1 in. (2cm) in diameter. The fruits are reddish purple
to orange, ¾-1 in. (1.5-2.0 cm) in diameter, and appear in summer. Paper
mulberry may be confused with the exotic white mulberry and native trees
such as red mulberry, sassafras, basswood, and white poplar.
Paper mulberry exhibits
aggressive growth and quickly invades disturbed lands, displacing native
plants. It has a shallow root system that makes the trees susceptible to
blow over during high winds.
IN THE UNITED STATES
Paper-mulberry occurs in twenty eight states
in the Northeast, Southeast, and Midwest, and is reported to be invasive
in natural areas in the District of Columbia, Florida, Georgia, Louisiana,
Maryland, North Carolina, Oklahoma, Pennsylvania, South Carolina, Tennessee,
and Virginia. It is also identified as an invasive weed in over a dozen
countries around the world.
HABITAT IN THE UNITED STATES
thrives in open habitats such as forest and field edges, and in disturbed
Paper mulberry was known
from Florida as early as 1903 and was widely planted throughout the Southeast
as an ornamental and shade tree around dwellings. The inner bark has been
used from ancient times as a source of paper and Pacific cultures used it
to make barkcloth.
BIOLOGY & SPREAD
spreads both by seed and through vegetative expansion. The seeds are spread
far and wide by wildlife who feed on the fruits. Paper mulberry expands locally
by producing new plants from its roots.
the exception of one systemic herbicide used effectively by plant control
contractors in Florida, little information is available on control of this
plant. Manual and mechanical methods either alone or in combination with
herbicide treatment are also possible.
Biological control is not
currently available for this plant.
Basal bark, cut-stem, hack-and-squirt,
or injection methods of herbicide application are recommended because these
methods, if used properly, focus applications to target species, minimize
the overall amount of herbicide applied, and reduce environmental impacts.
Basal bark application of the systemic herbicide Garlon® 4 (triclopyr ester
@ 61.6% a.i.) with a 15-20% mix in horticultural oil will achieve effective
control. Garlon® 3A (triclopyr amine @ 44.4% a.i.) may be used with a 50%
mix in water for cut stump applications. Herbicide can also be applied using
a hatchet* to make angled cuts into the trunk, into which concentrated
herbicide is squirted from a hand-held spray bottle. For this method, use
a 10% mixture of Garlon® 4 in horticultural oil, or a 15% rate for larger
trees. Triclopyr products such as Brush-B-Gon® are available at many garden
and hardware stores.
*A "hypo-hatchet," a hatchet
equipped with a mechanism that automatically injects pre-measured amounts
of herbicide into cuts upon impact, may also be used.
Pull seedlings by hand when the
ground is moist.
Cut young plants to the ground,
repeating as necessary to control regrowth from sprouts.
USE PESTICIDES WISELY: ALWAYS READ THE ENTIRE PESTICIDE LABEL CAREFULLY, FOLLOW ALL MIXING AND APPLICATION INSTRUCTIONS AND WEAR ALL RECOMMENDED PERSONAL PROTECTIVE GEAR AND CLOTHING. CONTACT YOUR STATE DEPARTMENT OF AGRICULTURE FOR ANY ADDITIONAL PESTICIDE USE REQUIREMENTS, RESTRICTIONS OR RECOMMENDATIONS.
NOTICE: MENTION OF PESTICIDE PRODUCTS ON THIS WEB SITE DOES NOT CONSTITUTE ENDORSEMENT OF ANY MATERIAL.
SUGGESTED ALTERNATIVE PLANTS
variety of native trees are available as substitutes for paper mulberry,
including basswood (Tilia heterophylla), sassafras (Sassafras albidum),
red maple (Acer rubrum), hackberry (Celtis occidentalis), and
black gum (Nyssa sylvatica), to name just a few. Check with your local
native plant society for species that are suitable for your area.
Jil M. Swearingen, National Park Service, National
Capital Region, Center for Urban Ecology, Washington, DC
Ruark Cleary, Lisa Samuelson.
Chuck Bargeron, University of Georgia, invasive.org
N.C. 2001. A Paper on Mulberries and the Invasive Paper Mulberry. In: 16th
Annual Symposium, Florida Exotic Pest Plant Council, ed. anonymous.
September 11-14, St. Augustine, p. 18. (abstract).
Flora of North America. Volume 3. Broussonetia
Kartesz, J.T. 1999. A Synonymized
Checklist and Atlas with Biological Attributes for the Vascular Flora of
the United States, Canada, and Greenland. First Edition. In: Kartesz, J.T.,
and C.A. Meacham. Synthesis of the North American Flora, version 1.0. North
Carolina Botanical Garden, Chapel Hill, NC.
Langeland, K. and R. Stocker. 1997.
Control of Non-native Plants in Natural Areas of Florida. University of Florida,
Institute of Food and Agricultural Sciences.
Miller, Lorraine. 2000. Paper Mullberry, Broussenetia
papyrifera, Invasive Plant Species. USDA Forest Service, Southern Region,
National Forests in Florida. Protection Report R8-PR 46.
Morgan, E.C. and W.A. Overholt.
2004. Wildland Weeds: Paper Mulberry (Broussonetia payprifera).
Small, J.K. 1903. Flora of the Southeastern
United States. Pub. by author, New York. 1370 pp.
Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Paper Mulberry (Broussonetia papyrifera). http://www.invasive.org/weedus/subject.html?sub=5208.
USDA GRIN-NPGS Broussonetia papyrifera
(L.) Vent.USDA Plants Database
USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov).
National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Plant Conservation Alliance, Alien Plant Working Group.