Culture
Winter hardy to USDA Zones 10-11 where it is easily grown in average, medium moisture, well-drained soils in full sun. Tolerates light shade, but best flowering is in full sun. Intolerant of frost (requires minimum temperature of 35-40 degrees F.). Tolerates some drought, but best growth occurs with regular watering. Trees are basically evergreen, but are native to areas of Central and South America that have pronounced dry seasons where the trees exhibit semi-deciduous tendencies (leaflets drop during the dry season but reappear as soon as moisture returns). Thrives in high summer heat. Propagate by seed.
Noteworthy Characteristics
Albizia saman, synonymous with and formerly known as Samanea saman, is native to open woodland areas and prairies from Central America to Brazil. It has been introduced and has naturalized in a number of tropical areas around the world. This is an ornamental tropical shade tree that grows to 50-80' tall with a broad, flattened, umbrella-like crown spreading to 100' in diameter. Mature trees provide excellent shade. Compound, bipinnate leaves (to 12-15" long) with leaflets to 1.5" long. Leaves fold up on cloudy or rainy days and at night. When it rains, water can more easily reach the grass under the tree because of the folded leaves, often resulting in greener grass under the tree, hence the common name of rain tree. Tiny flowers appear in mass (usually in spring) in rounded, fluffy, pompom-like flower heads (each to 1 1/2 across). Protruding stamens (white below but crimson-pink above) give the flower head an overall pink appearance from a distance. Flowers are attractive to bees. One (infrequently two) flowers per head are followed by a flattened, bean-like seed pod (each to 8" long with 15-20 seeds per pod). Pulp inside the pod is sticky, sweet and edible for humans. Seeds are imbedded in the pulp. Pods are often used as stock feed. Wood is used for making furniture and carved bowls.
Genus name honors Filippo degli Albizzia, 18th century Italian naturalist, who introduced the genus to Italy in 1749.
Problems
Wilt is becoming a serious problem in many areas. Also susceptible to mimosa web worm. Self-seeding can produce numerous seedlings.
Uses
Impressive tropical shade tree. Along roads, parks and pastures. Generally considered to be an attractive landscape tree, but needs a large space. Avoid planting in areas where wilt is a problem.