Desert ironwood Olneya tesota

Desert ironwood (Olneya tesota) is an evergreen perennial tree in the Fabaceae family, native to Sonoran Desert (below 750 m; frost-sensitive). It grows 4–9 m (13–30 ft) tall and 5–8 m (16–26 ft) wide, wants full sun and low water, and is hardy to about -6 °C (21 °F). Space plants about 6 m (20 ft) apart.

Plan Desert ironwood in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.

Desert ironwood at a glance

Is Desert ironwood toxic?

• People: not known to be toxic
• Cats: not known to be toxic
• Dogs: not known to be toxic

No toxicity reported in ASPCA or standard poison references.

If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.

Companion planting: what to grow with Desert ironwood

Good neighbours

• good With Sweet corn: "Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils. Evidence C

Keep apart or take care

• caution With Alliums (onion family): Onions, garlic and leeks are said to stunt beans and peas (allium root exudates may reduce nodulation). Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
• caution With Alliums (onion family): Beans and peas are traditionally kept away from onions, garlic and leeks. Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
• caution With Fennel: Fennel is reported to suppress beans and peas growing next to it. Evidence C

See Desert ironwood in a botanical garden

It grows in this sample garden, which you can walk through in 3D:

• Desert Botanical Garden (3 plants)

Questions about Desert ironwood

How far apart should I plant Desert ironwood?

About 6 m (20 ft) apart, centre to centre. A mature plant spreads 5–8 m (16–26 ft).

Does Desert ironwood need full sun?

Full sun: at least 8 hours of direct sun a day.

How much water does Desert ironwood need?

Low water. Drought tolerance is high and waterlogging tolerance none.

How cold-hardy is Desert ironwood?

It tolerates about -6 °C (21 °F) once established, roughly USDA zone 9.

When does Desert ironwood flower?

From about May for 3–5 weeks (northern hemisphere; later in cold climates, earlier in warm ones).

Is Desert ironwood poisonous to cats and dogs?

For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. No toxicity reported in ASPCA or standard poison references.

What grows well with Desert ironwood?

"Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils.

Sources and evidence

Evidence grade B (B: extension service or peer-reviewed).

• Desert Botanical Garden plant collections and trails, Desert Botanical Garden, Phoenix
• USDA PLANTS Database, USDA NRCS

Notes and assumptions

• Desert plant: needs sharp drainage and little summer water once established; rots in wet, heavy soil.
• Wood so dense it sinks; a keystone nurse tree sheltering hundreds of species; lavender pea flowers in May.

Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.

Related plants

• Bush bean Phaseolus vulgaris
• Garden pea Pisum sativum
• Sweet pea Lathyrus odoratus
• Runner bean Phaseolus coccineus
• Broad bean (fava) Vicia faba
• Lima bean Phaseolus lunatus
• Cowpea (black-eyed pea) Vigna unguiculata
• Yardlong bean Vigna unguiculata subsp. sesquipedalis