The leopard tree, Caesalpinia ferrea, is a tall deciduous tree native to Brazil. As the tree ages, the outer bark darkens and will often peel back to reveal white, light brown and green layers beneath. The mottled appearance likely contributed to the commonly used name of leopard tree. Its hardiness and distinctive display have made the tree a landscaping favorite, frequently used on streets in urban areas. Other names for the plant include the Brazilian ironwood and pau-ferro.
At maturity, the leopard tree can reach a height of up to 60 feet (18.3 m) with a sturdy trunk that often branches near the ground. The pruning of lower branches early in its life will encourage a vertical presentation, forcing branching to begin much higher on the trunk. A very dense canopy forms over time providing shade under long, graceful branches covered with green compound leaves.
The double-compound leaf structure is about 5 inches (13 cm) in total length with individual elliptical leaflets measuring about 1 inch (2.5 cm). The separation between leaf nodes is pronounced, with measured lengths up to 3 inches (7.6 cm). A leopard tree's leaves will sometimes fold up at night, or when the tree itself sustains damage.
The tree usually blooms in early to late spring. Its flowers are yellow with red marks, and are about 1 inch (2.5 cm) in diameter. They occur in clusters with individual flowers attached by short stalks equidistant along a central stem. The blooms may not be fully appreciated in more mature trees, as most flowering occurs near the top, which can be out of easy view. It also produces flat, shiny seedpods.
Leopard trees prefer direct sunlight and do best in hot climates, though they can tolerate some light frosts. The tree has adapted to dry, low fertility soils in its native environment but thrives in a more enriched soil, mildly acidic to mildly alkaline, with good drainage and moderate moisture. Propagation by seed is generally successful, especially if the outer coating is lightly cut. Good results from the use of mature cuttings along with a rooting hormone have been reported, as well.
The wood of the leopard tree is very dense and durable. It is often used in cabinetry and in door or window frames. There are also medicinal properties associated with the tree. In Brazil, a tea made from the stem has been used in the treatment of diabetes. Scientific studies have found that the tree contains potentially useful anti-inflammatory and anti-cancer compounds.