Unlikely — Zone Mismatch
triffid weed (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
Triffid Weed 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 triffid weed under glass — a greenhouse is the only lift this wide the engine models.
A 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 Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
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 triffid weed against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Triffid Weed 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: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Triffid Weed 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 triffid weed, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether triffid weed 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: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Soil + Drainage Fit
Triffid Weed tolerates a wide pH range (pH 4-7.5) — 3.5 units, acid ground through alkaline — so soil acidity is rarely what limits it in North Carolina. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5 and 6.5 — 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, raised beds or amendment with compost solve it.
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. Triffid Weed 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 and drainage requirements from USDA PLANTS Database. North Carolina soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Triffid Weed in North Carolina — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 10-12 (USDA PLANTS Database)
- State Zones: 6a-9a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 11 - Mar 24 to Nov 10 - Nov 25 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Triffid Weed 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 triffid weed here specifically
Triffid Weed rates to USDA zones 10–12 and is hardy to about 60°F, but cold isn't the risk in North Carolina — wet is: with roughly 14.7% of its soils poorly-drained (SSURGO), soggy ground rots the crown.
Give triffid weed a raised bed or mounded row with coarse amendment so its crown never sit wet. How to handle it →
What to actually do about these — and the constraints that apply to every North Carolina grower, not just triffid weed — 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 triffid weed 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 Triffid Weed Is Zone-Hardy
Triffid Weed 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 triffid weed needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Triffid Weed’s zone 10–12 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Triffid Weed draws honeybees, native bees, and butterflies (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, triffid weed 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.
Good to Know Before You Plant Triffid Weed
Triffid Weed is listed as toxic to dogs, cats (all) at a mild level (Cornell). 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 triffid weed, the canonical source is NC State Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Triffid Weed native to North Carolina?
Triffid Weed is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in North Carolina. It can still earn a place in a North Carolina garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The North 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 Triffid Weed in North Carolina
When can I plant Triffid Weed 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 Triffid Weed, 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 Triffid Weed grown in across North Carolina?
North Carolina spans USDA hardiness zones 6a-9a (USDA ARS PHZM 2023). Triffid Weed carries a range of zones 10-12, so the overlap zones are where outdoor growing is most reliable.
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). Triffid Weed should be matched against that window, 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 Triffid Weed native to North Carolina?
Triffid Weed is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in North Carolina. It can still earn a place in a North Carolina garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Triffid Weed in North Carolina?
Triffid Weed tolerates pH 4-7.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3.5-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a North Carolina site — amend for drainage and organic matter first.
Will Triffid Weed actually grow on my specific land in North Carolina?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores triffid weed 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 North Carolina
State-level data is a sketch. Your Growable Ground report scores triffid weed against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that North Carolina triffid weed 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 triffid weed average
Explore More
Growing guides for triffid weed
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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