Conditional — Some Areas
red tasselflower (zones 8-11) reaches only part of Oklahoma (6b-8b): zone 8 are in range, so where you are in the state decides it.
Your yard isn't the whole zone.
Red Tasselflower is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Oklahoma site runs ~237 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score red tasselflower against your land's actual frost dates, sun, and soil.
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Zone Comparison
Red Tasselflower Needs
- USDA Zones: 8-11
- Frost-Free Days: 90+
- Sun: Full Sun
- Picking window: ~90 days of harvest
Oklahoma Has
- USDA Zones: 6b-8b
- Last Hard Freeze (28°F): Mar 15 - Mar 26
- First Hard Freeze (28°F): Nov 9 - Nov 14
- Annual Rainfall: 15-56 inches
- Common Soils: Red clay, Sandy loam, Prairie loam
Plant Zone Range (zones 8-11)
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 Red Tasselflower in Oklahoma
The frost window
Across Oklahoma, the last spring hard freeze (28°F) clears between Mar 15 and Mar 26, and the first fall hard freeze lands between Nov 9 and Nov 14 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 228-day window you can count on — up to 244 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.
Frost tenderness
Red Tasselflower is frost-tender — its listed minimum temperature is 50°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
When to start the seed
Those dates are when red tasselflower goes out, not when it starts. It is sown under cover about 6 weeks ahead, so counting back from Oklahoma's late-side last freeze of Mar 26 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
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 red tasselflower survives winter in part of Oklahoma, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Red Tasselflower wants 90+ frost-free days; a typical Oklahoma site sees ~237 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
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
Red Tasselflower tolerates a wide pH range (pH 4-7) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Oklahoma. 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 4.5 and 6.5 — worth knowing before you decide whether a Oklahoma soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Oklahoma 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. Oklahoma soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Red Tasselflower in Oklahoma — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 8-11 (USDA PLANTS Database)
- State Zones: 6b-8b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 15 - Mar 26 to Nov 9 - Nov 14 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Red Tasselflower in Oklahoma
Zone compatibility tells you about winter cold survival — but Oklahoma growers also need to think about:
Extreme weather variability (tornadoes, ice storms, drought)
Red clay soils drain poorly in central OK
Low western rainfall requires irrigation
What to actually do about these — and the constraints that apply to every Oklahoma grower, not just red tasselflower — is covered on the Oklahoma growing guide.
Timing shifts within Oklahoma
Red Tasselflower needs about 90 days of frost-free season to complete its cycle. Even Cimarron County — Oklahoma’s shortest season at 197 frost-free days — clears that by 107 days, so season length isn’t the constraint anywhere in Oklahoma. What varies is your own parcel.
Across Oklahoma’s 77 counties the frost-free season runs from 197 days in Cimarron County to 267 days in Choctaw County — a spread of 70 days, which is why a single statewide planting date misleads. The median Oklahoma county sees 237 frost-free days, leaving red tasselflower about 147 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"). Red Tasselflower's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in Oklahoma Fits Best
Even within Oklahoma's zones 6b-8b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for red tasselflower (USDA PHZM 2023):
Pollinator + Wildlife Value
Red Tasselflower draws honeybees and native bees (low value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, red tasselflower can only work that bloom inside Oklahoma's frost window — roughly 237 days, opening after the last 28°F freeze (Mar 15 - Mar 26) and closing at the first (Nov 9 - Nov 14), per NOAA Regional Climate Centers ACIS, 1991-2020.
Oklahoma Cooperative Extension
For Oklahoma-specific cultivar recommendations, planting calendars, and pest pressure for red tasselflower, the canonical source is Oklahoma State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Red Tasselflower native to Oklahoma?
No — the USDA PLANTS Database lists Red Tasselflower as introduced rather than native in the Lower 48, so it is not part of Oklahoma's native flora. It grows here as a garden plant; pairing it with a few Oklahoma natives keeps local pollinators fed too.
Looking for plants that belong here? The Oklahoma 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 Red Tasselflower in Oklahoma
When can I plant Red Tasselflower in Oklahoma?
Oklahoma's last spring hard freeze (28°F) clears between Mar 15 and Mar 26, and the first fall hard freeze lands between Nov 9 and Nov 14 (NOAA Regional Climate Centers ACIS, 1991-2020). Red Tasselflower is frost-tender — its listed minimum temperature is 50°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
What hardiness zone is Red Tasselflower grown in across Oklahoma?
Oklahoma spans USDA hardiness zones 6b-8b (USDA ARS PHZM 2023). Red Tasselflower carries a range of zones 8-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Oklahoma site have?
A typical Oklahoma site sees ~237 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Red Tasselflower needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Red Tasselflower native to Oklahoma?
No — the USDA PLANTS Database lists Red Tasselflower as introduced rather than native in the Lower 48, so it is not part of Oklahoma's native flora. It grows here as a garden plant; pairing it with a few Oklahoma natives keeps local pollinators fed too.
How should I amend the soil for Red Tasselflower in Oklahoma?
Red Tasselflower tolerates pH 4-7 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Oklahoma site — amend for drainage and organic matter first.
Will Red Tasselflower actually grow on my specific land in Oklahoma?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores red tasselflower 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 Oklahoma
State-level data is a sketch. Your Growable Ground report scores red tasselflower against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Oklahoma red tasselflower averages can't show:
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