Unlikely — Zone Mismatch
ironwood (zones 10-13) does not overlap with South Carolina's zone range (7a-9b). 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 South Carolina is zone 9 — 1 zone short. Planted in open ground it will not survive a South Carolina 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 7-9 (South Carolina). 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.
South Carolina spans zones 7a-9b, 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.
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Zone Comparison
Ironwood Needs
- USDA Zones: 10-13
- Frost-Free Days: 365+
- Sun: Full Sun
- Drought tolerance: High
South Carolina Has
- USDA Zones: 7a-9b
- Last Hard Freeze (28°F): Feb 27 - Mar 12
- First Hard Freeze (28°F): Nov 23 - Dec 1
- Annual Rainfall: 45-55 inches
- Common Soils: Red clay (Piedmont), Sandy loam (Coastal), Alluvial
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 South Carolina
The frost window
Across South Carolina, the last spring hard freeze (28°F) clears between Feb 27 and Mar 12, and the first fall hard freeze lands between Nov 23 and Dec 1 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 256-day window you can count on — up to 277 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
South Carolina runs as cold as USDA zone 7, 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 South Carolina; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Chester 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 South Carolina 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 South Carolina under protection.
Frost-free days
Ironwood wants 365+ frost-free days; a typical South Carolina site sees ~265 (NOAA Regional Climate Centers ACIS, 1991-2020) — 100 days short of what it needs. A typical South Carolina 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 South Carolina's red clay (piedmont) and sandy loam (coastal) — a soil test confirms it for your site.
Your land, not the state average
South Carolina soil pH runs about 5.0–5.5, and that sits below ironwood's tolerated 6.8–8.6, so the typical South Carolina parcel needs lime before it will perform. SSURGO maps it swinging by full points parcel to parcel, so your map unit, not the state number, decides whether ironwood needs lime or sulfur.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. South Carolina soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Ironwood in South Carolina — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 10-13 (USDA PLANTS Database)
- State Zones: 7a-9b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Feb 27 - Mar 12 to Nov 23 - Dec 1 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Ironwood in South Carolina
Zone compatibility tells you about winter cold survival — but South Carolina growers also need to think about:
Red Piedmont clay requires amendment for drainage
High heat and humidity promote diseases
Hurricane risk along the coast
Growing ironwood here specifically
Ironwood wants soil pH 6.8–8.6, but South Carolina's soils run acidic (SSURGO maps a dominant pH near 5.2) — below its range, nutrients lock up and growth stalls.
Test your soil and lime to raise pH into ironwood's 6.8–8.6 range before planting. How to handle it →
What to actually do about these — and the constraints that apply to every South Carolina grower, not just ironwood — is covered on the South Carolina growing guide.
Timing shifts within South Carolina
South Carolina isn't one climate. In Chester County, the last hard freeze (28°F) holds until about Mar 22 — roughly 14 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 South Carolina county gives it that outdoors: even Charleston County, the state’s longest season at 320 frost-free days, falls 45 days short — so it needs transplants, a short-season variety, or covered growing.
Across South Carolina’s 46 counties the frost-free season runs from 237 days in Chester County to 320 days in Charleston County — a spread of 83 days, which is why a single statewide planting date misleads. The median South Carolina county sees 265 frost-free days, which is 100 days short of what ironwood needs — so on a typical South Carolina 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.
South Carolina Cooperative Extension
For South Carolina-specific cultivar recommendations, planting calendars, and pest pressure for ironwood, the canonical source is Clemson Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Ironwood native to South Carolina?
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 South Carolina. It can still earn a place in a South Carolina garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The South Carolina 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 South Carolina
When can I plant Ironwood in South Carolina?
South Carolina's last spring hard freeze (28°F) clears between Feb 27 and Mar 12, and the first fall hard freeze lands between Nov 23 and Dec 1 (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 South Carolina 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 South Carolina?
South Carolina spans USDA hardiness zones 7a-9b (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 South Carolina site have?
A typical South Carolina site sees ~265 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 Chester, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Ironwood native to South Carolina?
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 South Carolina. It can still earn a place in a South Carolina garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Ironwood in South Carolina?
Ironwood prefers pH 6.8-8.6 (USDA PLANTS). That sits in the common-ground band across South Carolina 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 South Carolina?
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 South Carolina
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 South Carolina ironwood averages can't show:
We read public map data around South Carolina — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the South Carolina ironwood average
Explore More
Growing guides for ironwood
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
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