Pronounciation: Pro-SO-pis chi-LEN-sis

Hardiness zones:
Sunset 12-13
USDA 9-11 (arid and semi arid regions only)

Landscape Use: Summer shade tree for dry or oasis landscapes of all types, city and desert parks, large commercial, industrial, and institutional landscape spaces, large (greater than 10 feet wide) landscape street and parking lot medians.

Form & Character: Upright and spreading, develops a broadly umbrella-shaped form when mature that is more symmetrical than Prosopis alba. Though Chilean mesquite has a symmetrical form, its inner crown branch topology is chaotic, rugged trunk and crown character.

Growth Habit: Chilean mesquite is a semi-evergreen, woody, broadleaf perennial tree. Its rate of growth is strongly depended on water availability. If water is available, then the shoot growth rate is rapid. Well-watered trees can exceed 50-feet tall with a much greater spread (up to 100 feet in diameter). In Phoenix, Chilean mesquite remains semi-dormant each year from December to April.

Foliage/Texture: Chilean mesquite has bipinnate compound leaves that are 4- to 6-inches long. Numerous pairs of leaflets range from 1/2- to 1-inch long. At the base of leaves are a pair of variably dangerous stipular spines that range in length from non-existent to 3-inches long.

Important note: Foliage of Chilean mesquite is typically larger than Prosopis alba.

Flowers & Fruits: Greenish, yellow flowers in 2-inches long catkins in April, flowers attract bees; fruit an elongated and slightly twisted light brown pod, ripens in July. Indehiscent, ripened fruits fall off the tree all at once usually around July 15th, edible.

Seasonal Color: None

Temperature: Highly tolerant of desert heat. Injured by temperatures below 20^oF.

Light: Full sun, no shade.

Soil: Highly tolerant of Sonoran Desert soil conditions. In fact, Chilean mesquite performs best in native, unamended desert soil.

Watering: None to occasional summer irrigations to encourage vigor only if needed. DO NOT irrigate regularly as this will cause the tree to grow structurally weak wood. Chilean mesquite is NOT a lawn tree.

Pruning: Train rigorously when young to form a strong, straight trunk and well-spaced system of scaffold branches. Otherwise, crown raise and thin mature mesquite trees to improve under canopy access, remove occasional suckers and water sprouts (weakly attached epicormic shoots), and decrease wind resistance to reduce risk of wind thrown in irrigated sites.

Propagation: Seed, acid scarification; air layering and stem cutting propagation is difficult.

Disease and Pests: Bacterial wet wood

Additional comments: In Phoenix, South American mesquites are hybrids of Propsopis alba and Prosopis chilensis, and are popular because of their rapid growth, apparent lower water requirement and strong shading potential. But beware of their aggressive, rangy and spreading habit. Many, if not most, of today's nursery selections are cloned superior hybrid crosses between these two species that grow no stipular spines.

Mesquite allergies: There is a growing body of anecdotal evidence to suggest that contact with mesquite foliage and pollen mght be an allergen.