Silktree, Mimosa (Albizia julibrissin)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Fabales
Family	Fabaceae
Genus	Albizia

Scientific Name

Albizia julibrissin

Common Name

mimosa

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, leguminous tree 10 to 50 feet (3 to 15 m) in height with single or multiple boles, smooth light-brown bark, feathery leaves, and showy pink blossoms that continually yield dangling flat pods during summer. Some pods persistent during winter.

Stem

Twigs slender to stout, lime green turning shiny grayish brown with light dots (lenticels). No terminal bud. Bark glossy, thin, light brown turning gray with raised corky dots and dashes.

Leaves

Alternate, bipinnately compound 6 to 20 inches (15 to 50 cm) long with 8 to 24 pairs of branches and 20 to 60 leaflets per branch, feathery and fernlike. Leaflets asymmetric, 0.4 to 0.6 inch (1 to 1.5 cm) long, dark green, with midvein nearer and running parallel to one margin. Margins entire.

Flowers

May to July (and sporadically to November). Terminal clusters at the base of current year twigs, each with 15 to 25 sessile flowers 1.4 to 2 inches (3.5 to 5 cm) long. Pompom-like with numerous filaments, bright pink feathery tufts with white bases. Fragrant.

Fruit and seeds

June to February. Legume pods in clusters, flat with bulging seeds, each pod 3 to 7 inches (8 to 18 cm) long, splitting in winter along the edges to release 5 to 10 oval seeds or disperse whole to float on water. Initially light green turning dark brown in fall and whitish tan in winter.

Ecology

Occurs on dry-to-wet sites and spreads along streambanks, preferring open conditions but also persisting in shade. Can form dense stands on abandoned farmland and home sites. Negatively impacts wildlife dependent on native vegetation. Seldom found above 3,000 feet (900 m). Forms colonies from root sprouts and spreads by abundant animal- and water-dispersed seeds. Seeds remain viable for many years. Nitrogen fixer.

Resembles

Resembles honeylocust (Gleditsia triacanthos L.) and locusts (Robinia spp.), which have longer leaflets—1 to 2 inches (2.5 cm to 5 cm) long. Also resembles seedlings of partridge pea [Chamaecrista fasciculata (Michx.) Greene], an annual plant with once pinnately compound leaves, and littleleaf sensitive-briar (Mimosa microphylla Dryand.), a reclining legume with fine prickles.

History and use

A traditional ornamental introduced from Asia in 1745. Potential use for forage and biofuel.

Distribution

Found as scattered plants or dense infestations in forests and along highways and roadsides throughout the region.

Management strategies

• Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of seed pods in a dumpster or burn.
• Minimize disturbance where this plant occurs.
• Treat when new plants are young to prevent seed formation.
• Cut and bulldoze when seed are not present.
• 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.

Recommended control procedures

Trees. Make stem injections using Arsenal AC* or when safety to surrounding vegetation is desired, Garlon 3A in dilutions as specified on the herbicide label (anytime except March and April). For felled trees, apply the herbicides to stump tops immediately after cutting. 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 a basal spray to young bark using Garlon 4 as a 20-percent solution (5 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); or undiluted Pathfinder II. Elsewhere, apply Stalker* as a 6- to 9-percent solution (1.5 to 2 pints per 3-gallon mix) in a labeled basal oil product, vegetable oil, kerosene, or diesel fuel (where permitted).

Resprouts and seedlings. Thoroughly wet all leaves with one of the following herbicides in water with a surfactant:

• From June to August, either Escort XP* at 1 ounce per acre (0.2 ounces per 3-gallon mix) plus a glyphosate herbicide as a 2-percent solution addition (8 ounces per 3-gallon mix) or Milestone VM* at 6 to 9 pints per acre (1.5 to 3 pints per 3-gallon mix and 10 gallons per acre).
• From July to September, Transline* † as a 0.25-percent solution plus Garlon 3A as a 4-percent solution (1 ounce plus 1 pint per 3-gallon mix).

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

† Transline controls a narrow spectrum of plant species.

Images

August	November	June
June	November	January	February

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