Unlikely — Zone Mismatch
ironwood (zones 10-13) does not overlap with New Mexico's zone range (5a-9a). Growing outdoors is unlikely without significant protection.
One zone short — what would close it
Ironwood is hardy to zone 10, and the warmest ground in New Mexico is zone 9 — 1 zone short. Planted in open ground it will not survive a New Mexico winter. To grow it here, grow ironwood in a container and move it under cover for the coldest weeks, or give it a greenhouse.
Season extension and overwintering under cover both work at this margin. How to buy the weeks →
Zone math from 10-13 (plant) against 4-9 (New Mexico). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
New Mexico spans zones 5a-9a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score ironwood against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Zone Comparison
Ironwood Needs
- USDA Zones: 10-13
- Frost-Free Days: 365+
- Sun: Full Sun
- Drought tolerance: High
New Mexico Has
- USDA Zones: 5a-9a
- Last Hard Freeze (28°F): Mar 31 - Apr 19
- First Hard Freeze (28°F): Oct 22 - Nov 9
- Annual Rainfall: 8-20 inches
- Common Soils: Sandy loam, Caliche, Adobe clay
Plant Zone Range (zones 10-13)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Ironwood in New Mexico
The frost window
Across New Mexico, the last spring hard freeze (28°F) clears between Mar 31 and Apr 19, and the first fall hard freeze lands between Oct 22 and Nov 9 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 186-day window you can count on — up to 223 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Winter standing
New Mexico runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for ironwood, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether ironwood is a permanent planting or a replant-every-spring crop for you turns on your own zone within New Mexico; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Catron County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says ironwood does not survive a New Mexico winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on New Mexico under protection.
Frost-free days
Ironwood wants 365+ frost-free days; a typical New Mexico site sees ~209 (NOAA Regional Climate Centers ACIS, 1991-2020) — 156 days short of what it needs. A typical New Mexico season does not carry this crop to harvest outdoors, and a gap that size is not one an earlier sowing date or a faster cultivar closes; growing it here means growing it under cover.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Ironwood likes near-neutral soil (pH 6.8-8.6). That's the common-ground band across New Mexico's sandy loam and caliche — a soil test confirms it for your site.
Your land, not the state average
New Mexico's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for ironwood is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how ironwood performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. New Mexico soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Ironwood in New Mexico — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 10-13 (USDA PLANTS Database)
- State Zones: 5a-9a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 31 - Apr 19 to Oct 22 - Nov 9 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Ironwood in New Mexico
Zone compatibility tells you about winter cold survival — but New Mexico growers also need to think about:
Very low rainfall requires irrigation for most crops
High altitude UV intensity can burn tender transplants
Alkaline soils limit plant selection without amendment
Growing ironwood here specifically
Ironwood needs pH 6.8–8.6; New Mexico's dominant loam soils may or may not deliver that, so your parcel's SSURGO map unit is the real test.
Start with a soil test on your own ground and adjust pH and texture to fit ironwood's 6.8–8.6 range. How to handle it →
What to actually do about these — and the constraints that apply to every New Mexico grower, not just ironwood — is covered on the New Mexico growing guide.
Timing shifts within New Mexico
New Mexico isn't one climate. In Catron County, the last hard freeze (28°F) holds until about May 22 — roughly 43 days later than the recorded state median — so plant ironwood to your county's window, not the statewide date.
Ironwood needs about 365 days of frost-free season to complete its cycle. No New Mexico county gives it that outdoors: even Doña Ana County, the state’s longest season at 264 frost-free days, falls 101 days short — so it needs transplants, a short-season variety, or covered growing.
Across New Mexico’s 33 counties the frost-free season runs from 144 days in Catron County to 264 days in Doña Ana County — a spread of 120 days, which is why a single statewide planting date misleads. The median New Mexico county sees 209 frost-free days, which is 156 days short of what ironwood needs — so on a typical New Mexico parcel this is a transplant-or-protect crop, not a direct-sow one.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Ironwood's 365-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
New Mexico Cooperative Extension
For New Mexico-specific cultivar recommendations, planting calendars, and pest pressure for ironwood, the canonical source is NMSU Cooperative Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Ironwood native to New Mexico?
Ironwood is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in New Mexico. It can still earn a place in a New Mexico garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The New Mexico growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Ironwood in New Mexico
When can I plant Ironwood in New Mexico?
New Mexico's last spring hard freeze (28°F) clears between Mar 31 and Apr 19, and the first fall hard freeze lands between Oct 22 and Nov 9 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Ironwood, so this page does not state whether it overwinters in New Mexico and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Ironwood grown in across New Mexico?
New Mexico spans USDA hardiness zones 5a-9a (USDA ARS PHZM 2023). Ironwood carries a range of zones 10-13, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical New Mexico site have?
A typical New Mexico site sees ~209 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Ironwood needs 365+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Catron, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Ironwood native to New Mexico?
Ironwood is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in New Mexico. It can still earn a place in a New Mexico garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Ironwood in New Mexico?
Ironwood prefers pH 6.8-8.6 (USDA PLANTS). That sits in the common-ground band across New Mexico soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Ironwood actually grow on my specific land in New Mexico?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores ironwood against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in New Mexico
State-level data is a sketch. Your Growable Ground report scores ironwood against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that New Mexico ironwood averages can't show:
We read public map data around New Mexico — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Mexico ironwood average
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
Last updated: