Common Name(s): Ironwood, Arizona Ironwood

Synonym(s):

Family: Fabaceae

Native To: Sonoran Desert of US and Mexico

Native Habitat: Washes and valleys of low desert

Growth Habit: Small sparse trees usually about 15-25 feet in height

Flowering: From April to about June with clusters of pink pea-like flowers

Distinguishing Characteristics: Trees grow to 25 ft tall, slow growing and long lived. Bark is gray to white, and sheds. Leaves and twigs are covered with small hairs, which serve to protect the tree from the worst of the hot sun. Leaves are dull green, divided into 6-16 leaflets. Small spines can be curved or straight. Flowers are pea-shaped and pale pink to purple. Dark brown 2” seed pods develop in June - July in Tucson.

Natural History and Cultivation Notes: Ironwood is an important species in the Sonoran Desert ecology. It is the tallest growing tree in the Sonoran Desert and provides a needed micro-habitat for many desert species. It has very hard, strong, heavy wood that actually sinks in water. It is actually a drought deciduous tree, meaning during dry periods it will shed its leaves to preserve water and conserve its energy for flowering and regeneration after the spring rains. It is also the only species in its genus.

Ethnobotany: Ironwood trees are the source of very dense hard wood (which burns hot and does not float). Native cultures in both Arizona and Sonora made use of the wood for building and carving of bowls, etc. Ironwoods are “nurse” trees in the Sonoran Desert . Animals gather in the shade during the hottest months, and other cacti and small shrubs utilize the tree's canopy to shelter from the sun. Like other members of the family, Ironwood is a tree that gathers nitrogen from the soil, so leaf litter and seeds are particularly rich in nutrients.

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