Conditional — Some Areas
ranunculus (zones 8-10) reaches only part of Oklahoma (6b-8b): zone 8 are in range, so where you are in the state decides it.
Ranunculus in Oklahoma — the short answer
Ranunculus in Oklahoma: hardy in zones 8–10, part sun, against a state median of ~237 frost-free days.
- Plant zones
- 8-10
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Oklahoma zones
- 6b-8b
- USDA PHZM 2023
- Frost window
- Mar 15 - Mar 26 – Nov 9 - Nov 14
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 197 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.
Oklahoma spans zones 6b-8b, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score ranunculus against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Oklahoma is not one climate
A single Oklahoma answer averages 77 counties whose growing seasons are 70 days apart — from 197 frost-free days in Cimarron County to 267 in Choctaw County. Which end of that your land sits nearer changes what ranunculus can finish before the first hard freeze.
The middle half of 77 counties runs 229–244 days, with a median of 237 days — a 70-day span end to end.
Measured across 77 Oklahoma counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. 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 in Oklahoma Fits Best
Ranunculus is rated for zones 8–10 — a cold floor USDA puts at 10 to 20°F. Against Oklahoma’s 77 counties that band holds in 14 of them, and the line runs at Atoka County (zone 8a), the coldest county still inside it.
Inside zones 8–10
14 counties
- Bryan County · zone 8a
- Carter County · zone 8a
- Choctaw County · zone 8a
3 of 14 shown
Below the zone 8 floor
63 counties
- Beaver County · zone 6b
- Cimarron County · zone 6b
- Texas County · zone 6b
3 of 63 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.
Even within Oklahoma's zones 6b-8b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for ranunculus (USDA PHZM 2023):
Zone Comparison
Ranunculus Needs
- USDA Zones: 8-10
- Sun: Part Sun
- Mature size: 1.5 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Low
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 8-10)
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 Ranunculus 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 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.
What Else to Consider for Ranunculus 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 ranunculus — is covered on the Oklahoma growing guide.
Where in Oklahoma Ranunculus Is Zone-Hardy
Ranunculus is rated for USDA zones 8–10. 14 of Oklahoma’s 77 counties fall inside that band. The coldest that does is Atoka County at zone 8a. 63 counties sit below the plant’s zone 8 floor, where an unprotected plant is relying on snow cover and a mild year. Where you are in Oklahoma decides this one.
Across those 77 counties Oklahoma’s winter-low ladder runs from zone 6b in Beaver County to zone 8a in Tillman County — 1.5 USDA zones of spread, which is 15°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.
The planting window moves with it. Cimarron County holds its last hard freeze (28°F) until about Apr 13, while Choctaw County is clear by Mar 1 — 43 days apart. Set ranunculus out on your county’s date, not the state’s.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". Ranunculus’s zone 8–10 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
Ranunculus draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, ranunculus 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 ranunculus, the canonical source is Oklahoma State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Ranunculus in Oklahoma
When can I plant Ranunculus 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). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
What hardiness zone is Ranunculus grown in across Oklahoma?
Oklahoma spans USDA hardiness zones 6b-8b (USDA ARS PHZM 2023). Ranunculus carries a range of zones 8-10, 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). Ranunculus 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.
Will Ranunculus actually grow on my specific land in Oklahoma?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores ranunculus 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 ranunculus against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Oklahoma ranunculus averages can't show:
We read public map data around Oklahoma — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Oklahoma ranunculus average
Explore More
Growing guides for ranunculus
Explore Oklahoma county by county
Oklahoma carries 77 counties with their own USDA zone — a sample of the growing pages for ranunculus there:
Where else ranunculus grows
Ranunculus's zone band crosses state lines — these are the states closest to Oklahoma 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 Oklahoma
Oklahoma has a growing page for 1,020 plants — a rotating sample of the rest of the shelf.
Last updated: