desert ironwood
Olneya tesota · Fabaceae
desert ironwood (Olneya tesota) is a perennial tree in the Fabaceae family. It is native to North America. USDA records it as hardy in zone 9 and warmer, down to about 22°F.
At a glance
| Type | tree Derived |
|---|---|
| Lifecycle | perennial USDA |
| Native status | native USDA |
| Mature height | 25 ft USDA |
| Light | full-sun USDA |
| Water need | low USDA |
| Growth rate | slow USDA |
| Soil pH | 6.8–8.6 USDA |
| Bloom | March–April USDA |
| Flower color | Purple USDA |
| Hardiness zones | 9 and warmer USDA |
| Guild layer | understory Derived |
| Nursery availability | Field Collections Only USDA |
USDA quoted from the USDA PLANTS database · Derived computed by a fixed rule from those columns. No value on this page is estimated.
Growing conditions
It needs full sun. USDA rates it as having low water needs once established. Its drought tolerance is rated high. It will not tolerate waterlogged soil — USDA rates its anaerobic tolerance as none. It is recorded on soils from pH 6.8 to 8.6 — a broad range that spans acidic through mildly alkaline ground. Its cold limit is zone 9.
Size and growth
At maturity it reaches about 25 ft, making it a substantial woody plant. It grows slowly.
Bloom period
USDA records a bloom period of March through April. Flowers are purple.
A flowering date, not a pollinator rating.
Foliage, flower and season
Summer foliage is white-gray, fine in texture. Its flowers are conspicuous. Its fruit or seed heads are conspicuous, extending interest past flowering. Its active growth period is spring, summer, fall. USDA rates its lifespan as long.
What the site needs to provide
USDA records it across sites receiving 3 to 20 inches of annual precipitation. The low end of that band is genuinely arid, so it has a wide tolerance for dry country. It needs at least 365 frost-free days to finish its season. It roots to at least 12 inches. Fertility requirement: low — no feeding needed on ordinary garden soil.
Propagating it
Propagate it from seed, bare root and container stock. USDA records no cold-stratification requirement, so seed should germinate without a chilling period. Its seed spreads at a slow rate. It does not spread vegetatively, so it will stay where you put it.
Resilience and wildlife
Browsing animals find it moderately palatable, so expect deer and rabbits to take an interest. Its fire tolerance is rated none. Its growth form is recorded as multiple stem.
Role in a guild
Understory. In a layered planting this is the layer beneath the canopy, tall enough to hold structure but shaded from above. The layer is derived by a fixed rule from growth habit and mature height.
Tags
Related plants
Similar role and hardiness
- California wax myrtle Morella californica
Where this data comes from
Every value on this page comes from the USDA PLANTS database record for symbol OLTE, or is computed from those values by a fixed rule. Nothing here is estimated or model-generated. Where USDA publishes no value, this page omits the claim rather than filling the gap.
- Quoted from USDA PLANTS: active growth period, Bloom, Bloom end, browse palatability, cold stratification, Drought tolerance, Edible, fall conspicuous, fertility requirement, fire tolerance, Flower color, flower conspicuous, foliage color, foliage porosity winter, foliage texture, frost free days min, fruit conspicuous, growth form, Growth rate, Hardiness zones, Lifecycle, lifespan, Light, Mature height, Minimum temperature, Native status, Nitrogen fixation, Nursery availability, precipitation max in, precipitation min in, propagation, resprout ability, root depth in, seed spread rate, Soil pH, Soil pH (upper), Tolerance of wet soil, Toxicity, vegetative spread rate, Water need.
- Derived by a fixed rule from those columns: Guild layer, Type.
Read our full data sources and methodology.
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