Paper Mulberry (Broussonetia papyrifera)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Rosales
Family	Moraceae
Genus	Broussonetia

Scientific Name

Broussonetia papyrifera

Scientific Name Synonyms

Morus papyrifera

Papyrius papyriferus

Common Name

paper-mulberry

Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.

Plant

Deciduous, large shrub or tree to 50 feet (15 m) in height and boles to 2 feet (0.6 m) in diameter with a round crown. Often appears as a shrub, forming thickets from root sprouts. Broad oval leaves, sometimes deeply lobed on rapidly growing stems, softly hairy on the lower surface and scruffy above. Downy gray twigs with scattered prominent orange dots (lenticels). Shallow rooted and prone to windthrow. Separate male and female plants (dioecious).

Stem

Twigs moderately stout, zigzagging, dark to light gray, sometimes greenish to reddish brown, covered with silvery down with distinct orange dots (lenticels) when young. Oval leaf scars have protruding rims with stipular scars of light lines on both sides and a hairy, domed flower bud in winter. Branches smooth and mottled gray (green with algae at times) increasingly with protruding orange-tan lenticels, leaf and stipular scars. Pith white with woody diaphragms at nodes. Bark light gray, braided with pale orange to light tan stripes, becoming yellowish with age.

Leaves

Alternate, sometimes opposite or whorled, oval to heart shaped, 3 to 10 inches (7.5 to 25 cm) long, sometimes with 1 to 6 deeply rounded sinuses. Dark green and sandpapery above, whitish and velvety below. Margins finely serrate to sharply toothed except near the base. Petioles 2 to 5 inches (5.0 to 12.5 cm) long, light green, and hairy. Stipules quickly shed.

Flowers

April to May. Male and female flowers appear on separate plants. Clusters of tiny male flowers are elongate, woolly, and drooping, 2.5 to 3 inches (6 to 8 cm) long. Female flowers globular, 1 inch (2.5 cm) wide. Both pale green turning purple.

Fruit and seeds

July to August on female plants (rare in Southeast). Globular and compound, orange turning reddish purple, 0.7 to 1 inch (1.8 to 2.5 cm) wide, with many embedded or protruding tiny, red seeds.

Ecology

Rapid growing, forming thickets and dense stands in fencerows, disturbed sites, and forest edges. Colonizes by root sprouts and spreads by rarely produced animal-dispersed seeds.

Resembles

Resembles both the native red mulberry (Morus rubra L.) and the nonnative white mulberry (M. alba L.), which also have a mixture of lobed and unlobed shaped leaves but are not velvety hairy beneath and do not have rounded fruit (theirs are elongated).

History and use

Introduced in the mid-1700s from Japan and China as a rapidly growing shade tree. Used in ancient times by the Chinese to produce fibrous paper (thus the common name “paper”).

Distribution

Found as scattered plants or scattered dense infestations throughout the region.

Management strategies

• Do not plant. Remove prior plantings, and control sprouts. Bag and dispose of fruit in a dumpster or burn.
• Manually pull new seedlings and tree wrench saplings when soil is moist, ensuring removal of all roots.
• Burning treatments are suspected of having minimal topkill effect due to scant litter.
• Treatment combinations should be used that are appropriate for dense thickets with limited access. Access trails may need to be cut.

Recommended control procedures

Large trees. Make stem injections at cut-spacing specified on the herbicide label using Garlon 3A as a 10-percent solution (1 quart per 3-gallon mix) in water or a 15-percent solution (58 ounces per 3-gallon mix) for larger trees, or cut large stems and immediately treat the stump tops with Garlon 3A as a 30-percent solution (7 pints per 3-gallon mix) in water with a surfactant. ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X are effective undiluted for treating cut-stumps and available in retail garden stores (safe to surrounding plants).

Saplings. Apply basal sprays of Garlon 4 as a 20-percent solution (5 pints per 3-gallon mix) or when nontarget damage is not a concern, Stalker* as a 3-percent solution (12 ounces per 3-gallon mix) plus Garlon 4 as a 15-percent solution (3 pints per 3-gallon mix) in a labeled basal oil product, vegetable oil or mineral oil with a penetrant, or fuel oil or diesel fuel (where permitted).

Seedlings and saplings. Thoroughly wet all leaves with one of the following herbicides in water with a surfactant on young trees less than 10 feet tall (July to October): when safety to surrounding vegetation is desired, use Garlon 3A as a 2-percent solution (8 ounces per 3-gallon mix), Garlon 4 as a 0.5- to 2-percent solution (2 to 8 ounces per 3-gallon mix), or a glyphosate herbicide as a 3-percent solution (12 ounces per 3-gallon mix). If nontarget damage is not a concern, use Arsenal AC* as a 0.25-percent solution (1 ounce per 3-gallon mix) or Arsenal PowerLine* as a 0.5-percent solution (2 ounces per 3-gallon mix).

* Nontarget plants may be killed or injured by root uptake.

Images

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July	June	January	April
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