Mexico and Central America is the native range of lead tree, or Leucaena leucocephala. Lead tree was most likely distributed by man because of its many uses. This multipurpose tree is used for fuel wood, lumber, animal fodder, and green manure. Ornamental uses include windbreaks, shade trees, and erosion control. Lead tree may have been introduced into Florida for cattle fodder and controlling erosion. Found in Southern Florida, including the Florida Keys, lead tree can be seen along roadsides and hammock margins in Miami-Dade and Monroe counties. Lead tree is a Category II invasive species.
Lead tree is a shrub or small tree growing up to 16 feet in height with bipinnate leaves to 10 inches long. There are approximately 12 pairs of lanceolate shaped leaflets each about 9-12 mm long, 2-3.5 mm wide. These are oppositely arranged. Flowers grow clustered on the end of branches. Individual flowers are white, turning brown with maturity. Lead tree is a prolific seed producer. The dark brown seed pods are flat, roughly 4 to 6 inches long, with about 20 seeds. Seeds are glossy brown, oval, flat, 6 mm long.
In areas where lead tree is considered an invasive weed, it will forms dense thickets and displaces the native vegetation. Disturbed, cleared areas, coastal strands, outskirts of forests and canopy gaps are some locations regularly invaded by lead tree.
The first step in preventative control of lead tree is to limit planting and removal of existing plants within the landscape. If possible, removal should occur before seeds are produced.
Inform the public to refrain from purchasing, propagating, or planting lead tree due to its invasive tendencies. If used as a forage, grazing should be managed to prevent flowering and seed formation.
There are no known mechanical controls for lead tree. Continuous cutting will eventually kill larger trees. Frequent mowing or grazing will kill smaller plants.
An insect known as ‘jumping lice’, or the leucaena psyllid (Heteropsylla cubana), will damage plants but does not eliminate established plants. Goats will provide a large level of control if allowed to continuously graze.
Lead tree is sensitive to foliar-applied triclopyr. Triclopyr ester applied basal bark and stump bark is effective, while 2,4-D in combination with diesel fuel is effective for basal bark treatments.