Santa Rita Acacia
Mariosousa millefolia
Family: Fabaceae
OTHER NAMES
milfoil prickle-free acacia
CHARACTERISTICS
Deciduous, large shrub or small tree growing to about 12’x15’. White, fuzzy, rod-like flower spikes appear in summer into fall, followed by papery legume pods.
LANDSCAPE USE
Screening shrub or small tree.
Photo by southwestwanderer on iNaturalist
Mariosousa millefolia on SEINET
GROWING CONDITIONS
SUN Full sun
WATER Moderate to low water (more water if you want it to become a tree)
SOIL well-drained
BASIN mid to high
CONTAINER does ok but won’t reach potential size
HARDINESS hardy to at least 20°F
FEEDING low
ECOLOGY
Larval food plant for the marine blue butterfly (Leptotes marina) and moth larval food plant for the various owlet moths (family Noctuidae), and geometer moths (family Geometridae). Flowers attract butterflies and lots of other nectar feeders.
ETHNOBOTANY
Unknown.
NATURAL DISTRIBUTION
Found in rocky canyons and on hillsides from 4,000-5,500 ft, in Arizona, New Mexico, and northern Mexico.
TAXONOMY AND NAME
This species is in the Fabaceae, the legume family. There are 13 species of Mariosousa.
Formerly known as Acacia millefolia.
Mariosousa honors Mario Sousa, former Director of the Herbarium of the Instituto de Biología (MEXU), Universidad Autónoma de Mexico, who has done extensive work in Acacia systematics, millefolia means many leaved, referring to the numerous tiny leaflets of this species.
Most plants found in the US are bushy, only a few reaching tree status. Photo by Sue Carnahan, SEINET
Flower detail, photo by Sue Carnahan, SEINET
Flat seed pods follow the flowers, photo by Sue Carnahan, SEINET