Unlikely — Zone Mismatch
sea hibiscus (zones 10-12) does not overlap with North Carolina's zone range (6a-9a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Sea Hibiscus is hardy to zone 10, and the warmest ground in North Carolina is zone 8 — 2 zones short. Planted in open ground it will not survive a North Carolina winter. To grow it here, grow sea hibiscus in an earth-sheltered greenhouse — its modeled 2.5-zone lift covers this gap.
An earth-sheltered greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 10-12 (plant) against 6-8 (North Carolina). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['earth_sheltered'] (+2.5 zones) via api/fast_sections.py Unlock Engine v2.
Sea Hibiscus in North Carolina — the short answer
Sea Hibiscus in North Carolina: hardy in zones 10–12, full sun.
- Plant zones
- 10-12
- Rated hardy to zone 10 by Cal Poly SelecTree, checked Oct 2026. Ceiling: our plant database.
- North Carolina zones
- 6a-9a
- USDA PHZM 2023
- Frost window
- Mar 11 - Mar 24 – Nov 10 - Nov 25
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 178 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
North Carolina spans zones 6a-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 sea hibiscus 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 parcel report in seconds — read in full free for your first 14 days
North Carolina is not one climate
North Carolina’s winter-low ladder runs across 100 counties, from zone 6.5 in Avery County to zone 9 in Dare County. That is 25°F between the two counties’ average coldest night — the difference between sea hibiscus overwintering in the ground and coming under cover.
The middle half of 100 counties runs 7.5–8 zones, with a median of 8 zones — a 2.5-zone span end to end.
Measured across 100 North Carolina counties. USDA PHZM 2023, per county. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where Sea Hibiscus Stands in North Carolina
Sea Hibiscus is rated for zones 10–12 — a cold floor USDA puts at 30 to 40°F. No North Carolina county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about North Carolina winters, not about sea hibiscus.
Below the zone 10 floor
100 counties
- Avery County · zone 6b
- Swain County · zone 6b
- Watauga County · zone 6b
3 of 100 shown
Winter cold is the limit here — the same plant works in a container that comes under cover.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.
Zone Comparison
Sea Hibiscus Needs
- USDA Zones: 10-12
- Sun: Full Sun
North Carolina Has
- USDA Zones: 6a-9a
- Last Hard Freeze (28°F): Mar 11 - Mar 24
- First Hard Freeze (28°F): Nov 10 - Nov 25
- Annual Rainfall: 40-60 inches
- Common Soils: Red clay (Piedmont), Sandy loam (Coastal), Mountain loam
Plant Zone Range (zones 10-12)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Sea Hibiscus in North Carolina
The frost window
Across North Carolina, the last spring hard freeze (28°F) clears between Mar 11 and Mar 24, and the first fall hard freeze lands between Nov 10 and Nov 25 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 231-day window you can count on — up to 259 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
North Carolina runs as cold as USDA zone 6, and no sourced winter-hardiness floor is on record for sea hibiscus, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether sea hibiscus is a permanent planting or a replant-every-spring crop for you turns on your own zone within North Carolina; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Swain County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Soil + Drainage Fit
Sea Hibiscus likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across North Carolina's red clay (piedmont) and sandy loam (coastal) — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a North Carolina soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your North Carolina site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost.
Your land, not the state average
SSURGO maps about 14.7% of North Carolina as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Sea Hibiscus sits mid-range for drought tolerance, so either extreme can cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. North Carolina soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Sea Hibiscus in North Carolina
Zone compatibility tells you about winter cold survival — but North Carolina growers also need to think about:
Red Piedmont clay is hard to work and drains poorly
Humidity drives significant disease pressure
Hurricane risk on the coastal plain
Growing sea hibiscus here specifically
Sea Hibiscus roots run medium and prefer pH 5.5–7.5, but drainage comes first here: SSURGO maps about 14.7% of North Carolina as poorly or somewhat-poorly drained, and wet ground rots its crown before pH ever matters.
Plant sea hibiscus on a raised, gravel-amended berm so water drains fast and the crown stays dry. How to handle it →
What to actually do about these — and the constraints that apply to every North Carolina grower, not just sea hibiscus — is covered on the North Carolina growing guide.
Timing shifts within North Carolina
North Carolina isn't one climate. In Swain County, the last hard freeze (28°F) holds until about Apr 27 — roughly 41 days later than the recorded state median — so plant sea hibiscus to your county's window, not the statewide date.
County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Where in North Carolina Sea Hibiscus Is Zone-Hardy
Sea Hibiscus is rated for USDA zones 10–12. No North Carolina county reaches it. Even Dare County, the state’s mildest winter at zone 9a, sits below the plant’s zone 10 floor — so in open ground this one needs winter protection here, or a container that comes under cover.
Across those 100 counties North Carolina’s winter-low ladder runs from zone 6b in Avery County to zone 9a in Dare County — 2.5 USDA zones of spread, which is 25°F between the two counties’ average coldest night of the year. None of that range reaches the band sea hibiscus needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Sea Hibiscus’s zone 10–12 band: Rated hardy to zone 10 by Cal Poly SelecTree, checked Oct 2026. Ceiling: our plant database.. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Sea Hibiscus draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, sea hibiscus can only work that bloom inside North Carolina's frost window — roughly 245 days, opening after the last 28°F freeze (Mar 11 - Mar 24) and closing at the first (Nov 10 - Nov 25), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
Good to Know Before You Plant Sea Hibiscus
Sea Hibiscus is listed as toxic to pets. (Source: U.S. FDA Center for Veterinary Medicine, which lists the genus Hibiscus, not this species by name, as potentially dangerous to pets.) Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
North Carolina Cooperative Extension
For North Carolina-specific cultivar recommendations, planting calendars, and pest pressure for sea hibiscus, the canonical source is NC State Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sea Hibiscus native to North Carolina?
No — the USDA PLANTS Database lists Sea Hibiscus as introduced rather than native in the Lower 48, so it is not part of North Carolina's native flora. It grows here as a garden plant; pairing it with a few North Carolina natives keeps local pollinators fed too.
Looking for plants that belong here? The North Carolina growing guide lists plants that USDA PLANTS records growing in North Carolina and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.
State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.
Common Questions About Growing Sea Hibiscus in North Carolina
When can I plant Sea Hibiscus in North Carolina?
North Carolina's last spring hard freeze (28°F) clears between Mar 11 and Mar 24, and the first fall hard freeze lands between Nov 10 and Nov 25 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Sea Hibiscus, so this page does not state whether it overwinters in North 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 Sea Hibiscus grown in across North Carolina?
North Carolina spans USDA hardiness zones 6a-9a (USDA ARS PHZM 2023). Sea Hibiscus is listed for zones 10-12, which do not overlap them, so there is no zone in North Carolina where this page can call outdoor growing reliable. A parcel report resolves your own address's zone.
How many frost-free days does a typical North Carolina site have?
A typical North Carolina site sees ~245 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Sea Hibiscus needs 270+ 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 Swain, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Sea Hibiscus native to North Carolina?
No — the USDA PLANTS Database lists Sea Hibiscus as introduced rather than native in the Lower 48, so it is not part of North Carolina's native flora. It grows here as a garden plant; pairing it with a few North Carolina natives keeps local pollinators fed too.
How should I amend the soil for Sea Hibiscus in North Carolina?
Sea Hibiscus prefers pH 5.5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across North Carolina soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Sea Hibiscus actually grow on my specific land in North Carolina?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores sea hibiscus against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in North Carolina
State-level data is a sketch. Your Growable Ground report scores sea hibiscus against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that North Carolina sea hibiscus averages can't show:
We read public map data around North Carolina — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the North Carolina sea hibiscus average
Explore More
Growing guides for sea hibiscus
Explore North Carolina county by county
North Carolina carries 100 counties with their own USDA zone — a sample of the growing pages for sea hibiscus there:
Where else sea hibiscus grows
Sea Hibiscus's zone band crosses state lines — these are the states closest to North Carolina in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in North Carolina
North Carolina has a growing page for 1,011 plants — a rotating sample of the rest of the shelf.
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: