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Description

Exists as a shrub or small tree. Leaves are bi-pinnately compound and are up to 10 inches long, and have 11 - 17 pairs of leaflets. Leaflets are small and exist opposite each other. Flowers are white and occur in 0.5 - 1 inch diameter heads with peduncles (stems of flowers) 2 - 2.5 inches long. Seeds occur in clusters of 5 - 20 pods (4 - 6 inches long) per flower head and contain 8 - 18 seeds per pod. Lead tree is fast growing, reaching 25 - 50 feet in height and 20 inches in bole diameter in a period of 20 - 40 years.

Ecological Threat

Lead tree forms dense monospecific thickets when not heavily grazed or controlled. It threatens native plant communities, and leaves large areas of land unusable. Easily escapes cultivation and is difficult to eradicate once established.

Biology

A prolific seed producer that is self-fertile and readily grows from seeds dispersed by rodents, birds, and cattle. Will flower and seed throughout the year if moisture is available. Vigorously regrows after fire, from cut stumps, as well as cuttings.

History

Introduced first to Hawaii in 1864 and soon afterwards to the mainland United States in Florida and Texas as a high protein cattle fodder and for land reclamation and erosion control. Its wood is used for firewood and lumber. Given its origins in Mexico and Central America, this species is considered by some to be native to Texas. Wide distribution of this species by humans has obscured the true extent of its native range.

Native Origin

Native to Central and South America

Current Location

U.S. Habitat: Favors alkaline and limestone soils. Does best in wet conditions but is resistant to drought once established. River banks, cultivated areas, and pastures are prone to invasion. Requires warm temperatures; little resistance for cold.

U.S. Present: AZ, CA, FL, TX

Resembles

It resembles Mesquite trees from the genus Prosopis.

Management

Small individual plants may be manually removed, taking care to remove the roots. Controlled grazing before cattle can control it. On larger specimens or infestations, this option will probably not be feasible.

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.

References

Contributions from Texas Invasives for this species page are greatly appreciated.

Dhawan, V., & Bhojwani, S. S. (1985). In vitro vegetative propagation of Leucaena leucocephala (Lam.) de Wit. Plant cell reports, 4(6), 315-318.

Dommergues, Y. R., Diem, H. G., Gauthier, D. L., Dreyfus, B. L., & Cornet, F. (1984). Nitrogen-fixing trees in the tropics: potentialities and limitations. In Advances in nitrogen fixation research (pp. 7-13). Springer Netherlands.

The Quiet Invasion: A Guide to Invasive Plants of the Galveston Bay Area. Lisa Gonzalez and Jeff DallaRosa. Houston Advanced Research Center, 2006.

Internet Sources

http://www.tropicalforages.info/key/Forages/Media/Html/Leucaena_leucocephala.htm

http://www.issg.org/database/species/ecology.asp?si=23&lang=EN

http://www.hear.org/pier/species/leucaena_leucocephala.htm

http://www.hort.purdue.edu/newcrop/duke_energy/Leucaena_leucocephala.html