Common Name(s): Palo Blanco, Willard’s Acacia

Synonym(s):

Family: Fabaceae

Native To: Southwest Sonora and on the Sonoran islands of Tiburón and San Pedro Nolasco

Native Habitat:

Growth Habit: This acacia will grow up to 10-20ft or more with a spread of 1/3 to 2/3 its height. It is frost sensitive and is damaged in high twenties.

Flowering: Flowering occurs between February and July. (Note: a dry season may preclude flowering) The tree produces a tan, 3-4in. long, multi-chambered pod.

Distinguishing Characteristics: A slender unarmed tree 3-9 m tall with smooth white or cream colored papery exfoliating bark. Petioles are flattened phyllode-like (1.5-4 mm wide and 6-30mm long) but still bear leaflets. 2-8 pinnae bear 4-15 pairs of linear leaflets (2-5mm long).

Natural History and Cultivation Notes: Acacia willardiana is found in areas of rocky hill slope and hill crests between arid and semiarid climates where most of the rain comes in the warm season. Leaves are deciduous. Phyllodic petioles continue photosynthesis after leaves drop.

Ethnobotany: The wood of this tree is used by the Seri Indians of northern Mexico for miscellaneous uses such as hut construction. A rare amino acid, willardine, was originally discovered in A. willardiana.

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