Leucaena spp.
leadtrees
Tropical Americas (Mexico, Central America)
Overview
Leucaena spp. is a genus of about 24 species of fast-growing shrubs and trees in the pea family (Fabaceae), native to the tropical Americas, chiefly Mexico and Central America. Plants reach 15-65 ft (4.5-20 m) tall depending on species, with bipinnate, feathery leaves made up of many small leaflets. Globe-shaped heads of small white to cream flowers, each head 0.5-1 in (1.5-2.5 cm) across, are followed by clusters of flat, papery brown pods 4-10 in (10-25 cm) long that split to release rows of glossy brown seeds. The roots fix nitrogen, and combined with rapid growth this lets the plants colonise cleared and disturbed ground. The genus is native from Texas and Mexico through Central America to northern South America. L. leucocephala has been planted widely across the tropics for firewood, fodder, and soil improvement, and has become a troublesome invasive tree in many regions, forming dense thickets. The foliage and seeds contain the amino acid mimosine, which causes hair loss and other harm in non-ruminant animals that eat large amounts. The wood is brittle and branches break in storms.
Native Range
The genus is native to the tropical and subtropical Americas, from Texas and Mexico south through Central America to northern South America. Species grow in dry forest, thorn scrub, and on disturbed and cleared ground.Suggested Uses
Grown in the tropics for firewood, fodder, green manure, and quick shade or windbreaks on poor soil, mainly in agroforestry. Use is limited where the heavy seeding of L. leucocephala can spread into natural areas.How to Identify
Appearance
Size & Dimensions
Height15' - 65'
Width/Spread10' - 30'
Reaches mature size in approximately 5 years
Bloom Information
Flowering can occur through much of the warm season and, in the wet tropics, nearly year-round, with flushes after rain. The round white flower heads open over a few days and are insect-pollinated. Pods follow quickly and ripen within one to two months, often while new flowers are still opening.
Detailed Descriptions
Flower Description
white to creamFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-12 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
Plants grow in full sun and tolerate a wide range of soils, including poor, dry, rocky, and alkaline ground, though they grow poorly in waterlogged or strongly acid soil. Established plants are drought-tolerant and resprout strongly after cutting, drawing on deep roots and nitrogen fixation. Growth is rapid in warm climates, and plants flower and seed young. Most species are frost-tender and are cut back or killed by hard freezes. Heavy self-seeding and root suckering let stands spread quickly, so containment is often needed. The mimosine in the foliage limits its use as feed for non-ruminant livestock.Pruning
Plants are often coppiced or pollarded for fodder and firewood, resprouting readily from cut stumps. Seed pods are removed before they ripen on plants where self-seeding into surrounding land is a concern.Pruning Schedule
early spring