The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) spans USDA hardiness zones 7b-8a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Oklahoma's warmest, wettest, longest-season corner — a genuinely different growing world from the state core. The Ouachita Mountains and Kiamichi River country hold verified USDA zone 8a across the Red River bottomlands, with 243–267 frost-free days (Choctaw 267, McCurtain 249) — up to ~70 days longer than the Panhandle — over acidic, shortleaf-pine-forested mountain soils fed by roughly 50 inches of annual rain. A statewide reading (~zone 7a, central) misses all of it: the two higher northern counties (Le Flore, Latimer) even step down to 7b, so this region carries its own zone-and-season logic. The conditions favor okra, tomato, redbud, and pecan, among others — though every individual site edits that list with its own soil, sun, and drainage.
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) spans Oklahoma.
Your yard isn't all of the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country).
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) spans USDA zones 7b-8a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — soil, climate, flood, and parcel records. How we handle your address.
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The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — the short answer
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country): USDA zones 7b-8a, 231–267 frost-free days depending where in it you stand, in Oklahoma.
- USDA zones
- 7b-8a
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 231 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Le Flore County
- Counties
- 7
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. The season figure is this region's own record, measured across its 7 member counties, not a state or national average.
Hardiness Zone Range
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) is not one growing season
One answer for the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) averages 7 counties whose growing seasons are 36 days apart — from 231 frost-free days in Le Flore County to 267 in Choctaw County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 7 counties runs 240–249 days, with a median of 243 days — a 36-day span end to end.
Measured across 7 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
Where the line runs inside the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
The middle half of the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) runs 240–249 frost-free days, and 3 of its 7 counties sit outside that — 2 on the short side, 1 on the long. A regional planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 240 frost-free days
2 counties
- Le Flore County · 231 days
- Latimer County · 237 days
The end of the region that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
240–249 frost-free days
4 counties
0 of 4 shown
The middle half of the region, and the part a single regional season describes well.
Over 249 frost-free days
1 county
- Choctaw County · 267 days
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its OWN 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a site within its county as well — which is the part only your address resolves.
What Grows in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
All 2 of the plants below that publish a season requirement clear even Le Flore County’s 231 frost-free days — so on season alone, this grid works at both ends of the region. The 36-day spread still decides how far past this list you can push, and how early you can start.
Plants matched to the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s USDA zones 7b-8a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)’s USDA zones 7b-8a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
The USDA soil survey maps this ground county by county. These are those records weighted by land area across seven member counties — this region’s own profile, not a state figure.
The ground is predominantly Ultisols, at 39% of mapped acres, followed by Alfisols (31%), Inceptisols (11%) and Mollisols (8%). Six soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Carnasaw, Clebit, and Bernow.
61% of those acres are well drained, and another 25% moderately well drained, 7% somewhat poorly drained. Topsoil pH runs 5.3–7.2 between the lowest and the highest county on record. 29% of the footprint is classed prime farmland.
Soil order
Ultisols
Drainage
Well drained
Topsoil pH
5.3–7.2
Hydric soils
6%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Choctaw County holds the most wetland ground here, at 15% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
The soil survey reads this ground county by county, and the readings above are those records summed across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country). Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records61% of the mapped acres across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) are well drained — ground that drains quickly. That is area-weighted across all seven of its mapped counties.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) runs pH 5.3–7.2 — acidic in five of its seven counties.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — and how to grow with it.
Across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s 7 counties the federal record holds 1,072 documented sites, mostly Underground Storage Tanks (839), Brownfields (97) and Nitrate (62). The heaviest single county is McCurtain County, with 278.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) to see which records sit where you actually grow.
Sources Checked
Summed across the 7 counties in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
A note from Gnorman
What an experienced grower watches for around here
In and around the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country), two things run higher than the national average across the 7 counties in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — PFAS (16 sites) and Underground Storage Tanks (839 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
Everything above resolves to the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) as a whole — a footprint whose own counties record seasons 36 days apart, and hardiness across zones 7b-8a. Your parcel sits at one point in that range, not in the middle of it. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at region scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better regional average.
Your Lot vs the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) Average
Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) Average
- ●USDA Zones 7b-8a, averaged across Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
- ●One soil character for all of Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s 7b-8a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
Pull a site-specific report for your exact address in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) averages can't show:
We read public map data around The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) average
How we know this about the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
What hardiness zone is the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)?
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) spans USDA hardiness zones 7b-8a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)?
Measured between 28°F hard freezes, the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s counties mostly run 240 to 249 frost-free days, median 243 (NOAA Regional Climate Centers ACIS, 1991–2020, over 7 member counties). That 9-day spread is the honest read — no single season describes 7 counties, and each county guide below carries its own.
When does frost risk end in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)?
Across the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country), the middle half of member counties see their last 28°F hard freeze between Mar 14 and Mar 19 (median Mar 16), and their first fall freeze between Nov 13 and Nov 18. Those are hard freezes, not the last light frost: tender transplants wait for about Apr 6, and elevation decides which end of a 5-day spread you garden in.
What grows well in the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)?
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s conditions suit plants such as Okra, Tomato, Redbud, Pecan, Blackberry. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) defined?
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) is defined here as a curated cluster of 7 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) cover?
The Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country) spans Oklahoma. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
High Plains, The Ozarks, and Oklahoma Panhandle ("No Man's Land") share at least one state with the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country). Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)’s own scale
6 of the readings below were taken at the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)'s own scale — the zone 7b-8a band across its footprint, a median 243-day season across its 7 counties and 1,072 documented federal contamination records across its 7 counties, 278 of them in McCurtain County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7b-8a aggregated across all 7 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 7 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 7 counties run 240 to 249 frost-free days, median 243NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 1,072 documented federal contamination records across its 7 counties, 278 of them in McCurtain County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 39% Ultisols, topsoil pH 5.3–7.2, area-weighted across its 7 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 7b-8afrom Oklahoma
What this page can’t tell you
- Which end of the 9-day range your ground sits at — 240 days at one extreme, 249 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Southeastern Oklahoma / Ouachita Mountains (Kiamichi Country)
State growing guides
Counties in this region
Other growing regions across Oklahoma
A semi-arid shortgrass tableland of deep soils and big sky, where wind, low rainfall, and irrigation shape dryland wheat, sorghum, and resilient gardens.
A rugged Interior Highlands of cherty, rocky soils, oak-hickory forest, and clear streams — brambles, peaches, and tough hill gardens.
Oklahoma's only zone-6b ground: the three-county Panhandle — Cimarron, Texas, and Beaver, the historic "No Man's Land" — is the coldest, driest, shortest-season, and highest corner of the state. A 197-204-day frost-free window on semi-arid High Plains tableland near 4,000+ ft climbs to Black Mesa (4,973 ft), Oklahoma's highest point. This is dryland-wheat and grain-sorghum country where wind and irrigation, not the state's warmer ~7a core, decide what grows.