Ironwood
Olneya tesota
A keystone species of the Sonoran Desert, treasured for its dusty lavender blooms and extraordinary longevity.
Frost-sensitive when young, hardy to about 20°F; a low- and mid-desert Sonoran native that appreciates protection from hard frost while establishing.
AMWUA Notes
Extremely low water once established; a slow-growing keystone tree that needs almost no supplemental irrigation when mature.
Care Guide
Once established, water deeply once a month. Extremely drought tolerant and overwatering can cause root rot.
Minimal pruning needed. Remove dead branches in late winter. Natural form is attractive.
No fertilizer needed. Nitrogen-fixing legume tree.
Very few pest issues. Occasionally affected by leaf-footed bugs.
Beautiful lavender blooms in May. Evergreen to semi-evergreen.
Soil, Feeding & Propagation
Sharply draining sandy, gravelly, or decomposed-granite soil; tolerates caliche and alkaline pH 7.5–8.5 and resents wet ground
Needs sharp, fast-draining soil.
None — thrives in lean desert soil without fertilizer.
Grown from scarified seed; slow-growing, so start from established nursery stock
20–25 ft
Deep, non-aggressive roots are foundation-safe; keep 12+ ft from pools for thorns and pod litter
Placement Tips
- •Broad 25 ft evergreen canopy and a slow, long-lived habit make this a permanent specimen and nurse tree.
- •Medium thorns and seasonal flower and pod litter mean keeping it 12–15 ft from pools and walkways.
- •A keystone Sonoran species; pair with saguaro, palo verde, and understory wildflowers.
- •Full sun with sharp drainage; site once and leave undisturbed for its long life.
Features
Best Uses
Ecological Value
Wildlife Value
Companion Plants
Quick Stats
Design Styles
Include in Your Project
Love Ironwood? Our landscape team sources from wholesale nurseries and can incorporate it into your design.
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Use this care guide to maintain your Ironwood. Questions about your landscape? Reach out anytime.
Data from 2024 AMWUA “Landscape Plants for the Arizona Desert” guide.
Ironwood — common questions
Answers for low-desert Phoenix conditions, drawn from this plant’s growing data.
How much water does Ironwood need in Phoenix?
Ironwood is a very low-water tree once established. Once established, water deeply once a month. Extremely drought tolerant and overwatering can cause root rot. Extremely low water once established; a slow-growing keystone tree that needs almost no supplemental irrigation when mature.
How big does Ironwood get?
Expect roughly 25 ft tall and 25 ft wide at maturity, with a slow growth rate. Allow about 20–25 ft of spacing when planting. Deep, non-aggressive roots are foundation-safe; keep 12+ ft from pools for thorns and pod litter.
Can you plant Ironwood near a pool?
Not ideally. Ironwood is not rated pool-friendly, so it is better placed away from the pool deck and skimmer. Litter is rated seasonal.
Can Ironwood handle Arizona heat and winter frost?
Ironwood is hardy in USDA 9-11 and wants full sun. Frost-sensitive when young, hardy to about 20°F; a low- and mid-desert Sonoran native that appreciates protection from hard frost while establishing. Beautiful lavender blooms in May. Evergreen to semi-evergreen.
Does Ironwood have thorns?
Yes — Ironwood has medium thorns. Site it back from walkways, seating and pool decks where people brush past.
Is Ironwood safe around pets?
Ironwood is listed as pet-friendly in this guide. If your dog is a determined chewer, check any new plant with your vet before planting.
When does Ironwood bloom in Arizona?
Ironwood blooms in late spring, with dusty lavender flowers.
How much maintenance does Ironwood need?
Ironwood is moderate-maintenance. Leaf, flower and pod litter is rated seasonal. Minimal pruning needed. Remove dead branches in late winter. Natural form is attractive.
What kind of soil does Ironwood need?
Sharply draining sandy, gravelly, or decomposed-granite soil; tolerates caliche and alkaline pH 7.5–8.5 and resents wet ground. It needs no supplemental feeding. No fertilizer needed. Nitrogen-fixing legume tree.
Is Ironwood native to Arizona?
Yes. Ironwood is native to Arizona and to the Sonoran Desert, so it is adapted to local rainfall, soil and heat.