Can I Grow Tithonia in North Carolina?

USDA Zones 6a-9a · Plant zone range 2-11

Yes — Strong Match

tithonia (zones 2-11) covers every zone North Carolina contains (6a-9a), so hardiness is not what limits it anywhere in the state.

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Zone Comparison

Tithonia Needs

  • USDA Zones: 2-11
  • Sun: Full Sun
  • Mature size: 5 ft tall
  • Picking window: ~90 days of harvest
  • Drought tolerance: High

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 2-11)

2a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.57.5

Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Tithonia 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.

When to start the seed

Those dates are when tithonia goes out, not when it starts. It is sown under cover about 6 weeks ahead, so counting back from North Carolina's late-side last freeze of Mar 24 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

Winter standing

North Carolina runs as cold as USDA zone 6, and no sourced winter-hardiness floor is on record for tithonia, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether tithonia 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.

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 tithonia survives winter here. Whether the season is long enough — and warm enough — is a different question.

Days to maturity

Tithonia matures in ~80 days (Growable Ground Plant Database). A typical North Carolina site has ~245 frost-free days, so plenty of room for a second succession.

Growing degree days

Tithonia needs ~1800 GDD (base 50°F) to ripen. The state median runs ~4537 GDD (from PRISM 1991-2020 climate normals), so North Carolina's typical season clears that easily.

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

Tithonia 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, raised beds or amendment with compost solve it.

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.

Tithonia in North Carolina — Quick Answer

  • Verdict: Yes — Strong Match
  • Plant Zones: 2-11 (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)
  • Days to Maturity: 80 days

What Else to Consider for Tithonia 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

What to actually do about these — and the constraints that apply to every North Carolina grower, not just tithonia — is covered on the North Carolina growing guide.

Timing shifts within North Carolina

Tithonia needs about 80 days of frost-free season from planting to harvest. Even Swain County — North Carolina’s shortest season at 178 frost-free days — clears that by 98 days, so season length isn’t the constraint anywhere in North Carolina. What varies is your own parcel.

Across North Carolina’s 100 counties the frost-free season runs from 178 days in Swain County to 303 days in Dare County — a spread of 125 days, which is why a single statewide planting date misleads. The median North Carolina county sees 245 frost-free days, leaving tithonia about 165 days of slack on a typical parcel — room for a second sowing where the season runs long.

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"). Tithonia's 80-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.

Where in North Carolina Fits Best

Even within North Carolina's zones 6a-9a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for tithonia (USDA PHZM 2023):

Pollinator + Wildlife Value

Tithonia draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, tithonia 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.

North Carolina Cooperative Extension

For North Carolina-specific cultivar recommendations, planting calendars, and pest pressure for tithonia, the canonical source is NC State Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Tithonia native to North Carolina?

No — the USDA PLANTS Database lists Tithonia 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 USDA-documented natives for the state.

Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.

Common Questions About Growing Tithonia in North Carolina

When can I plant Tithonia 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 Tithonia, 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 Tithonia grown in across North Carolina?

North Carolina spans USDA hardiness zones 6a-9a (USDA ARS PHZM 2023). Tithonia carries a range of zones 2-11, 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). Tithonia 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.

Is Tithonia native to North Carolina?

No — the USDA PLANTS Database lists Tithonia 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 Tithonia in North Carolina?

Tithonia prefers pH 5.5-7.5 and well (dry spells) drainage (Growable Ground Plant Database). 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 Tithonia actually grow on my specific land in North Carolina?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores tithonia against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in North Carolina

State-level data is a sketch. Your Growable Ground report scores tithonia against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that North Carolina tithonia averages can't show:

Your soil pHYour frost-free days — North Carolina averages 245Your sun & shade

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 tithonia average

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