Desert Ironwood (Olneya tesota)
Another ancient staple of Sonoran Desert nitrogen fixation and edible beans, the mature desert ironwood is a majestic sight for anyone with eyes to see it.
Mature Canopy Size
20–30 ft wide, 20–30 ft tall
Growth Rate
Slow — 6–12 inches per year; moderate with regular deep watering
Water Requirements (Minimum vs. Maximum Growth)
Minimum: Very low — survives on rainfall once established
For Fast Growth: Monthly deep watering during summer accelerates canopy development
Ecological & Functional Benefits
Keystone species in the Sonoran Desert — shelters hundreds of desert species
Fixes nitrogen, improves soil, and acts as a “nurse plant” for other natives
Provides dense, cool shade; reduces ground temperatures dramatically
Edible / Harvest Season / Nutritional Benefits
Yes — ironwood bean pods are edible (and delicious when roasted)
Seeds high in protein and fat
Harvest late spring to early summer before pods fully harden
Indigenous food source for generations
Minimum Chill Hours
None — thrives in hot low desert zones with no chill requirement
Maintenance Requirements
Very low — occasional pruning when young to raise canopy or manage shape
Extremely long-lived and low-fuss
Thorny or Not?
Yes — small, sharp thorns along young branches
Deciduous or Not?
Semi-evergreen — may shed some leaves in extreme drought or cold
Root System
Deep and slow-growing, but not aggressive
Non-invasive to patios, sidewalks, and pool decking
Safe near hardscape and infrastructure if given 10–15 ft spacing
Tends to form a strong taproot early, making it drought-resilient and stable
Miscellaneous Notes
Wood is extremely dense — sinks in water
One of the longest-lived trees in the desert (can exceed 1,000 years)
Flowers (pale purple-pink) are highly attractive to pollinators
Difficult to transplant once mature — best planted young
Questions about the Desert Ironwood?
Comment below or on our social media pages @permascaping.
