kurrajong (Brachychiton populneus), photographi

Can I Grow Kurrajong in Kentucky?

USDA Zones 6a-7b · Plant zone range 9-11

Unlikely — Zone Mismatch

kurrajong (zones 9-11) does not overlap with Kentucky's zone range (6a-7b). Growing outdoors is unlikely without significant protection.

2 zones short — what would close it

Kurrajong is hardy to zone 9, and the warmest ground in Kentucky is zone 7 — 2 zones short. Planted in open ground it will not survive a Kentucky winter. To grow it here, grow kurrajong in an earth-sheltered greenhouse — its modeled 2.5-zone lift covers this gap.

An earth-sheltered greenhouse is the lift this needs. How a greenhouse changes what you can grow →

Zone math from 9-11 (plant) against 6-7 (Kentucky). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['earth_sheltered'] (+2.5 zones) via api/fast_sections.py Unlock Engine v2.

Kurrajong in Kentucky — the short answer

Kurrajong in Kentucky: hardy in zones 9–11, full sun, against a state median of ~221 frost-free days.

Plant zones
9-11
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
Kentucky zones
6a-7b
USDA PHZM 2023
Frost window
Mar 27 - Apr 2 – Nov 4 - Nov 10
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
195 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.

Score your parcel · free

Your yard isn't the whole zone.

Kentucky spans zones 6a-7b, 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 kurrajong against your parcel's actual hardiness, soil, and sun.

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

Kentucky is not one climate

Kentucky’s winter-low ladder runs across 120 counties, from zone 6.5 in Anderson County to zone 7.5 in Lyon County. That is 10°F between the two counties’ average coldest night — the difference between kurrajong overwintering in the ground and coming under cover.

6.5 zonesAnderson County7.5 zonesLyon County

The middle half of 120 counties runs 6.57 zones, with a median of 7 zones — a 1-zone span end to end.

Measured across 120 Kentucky counties. USDA PHZM 2023, per county. 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 Kurrajong Stands in Kentucky

Kurrajong is rated for zones 911 — a cold floor USDA puts at 20 to 30°F. No Kentucky county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Kentucky winters, not about kurrajong.

Below the zone 9 floor

120 counties

3 of 120 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.

Zone Comparison

Kurrajong Needs

  • USDA Zones: 9-11
  • Frost-Free Days: 90+
  • Sun: Full Sun

Kentucky Has

  • USDA Zones: 6a-7b
  • Last Hard Freeze (28°F): Mar 27 - Apr 2
  • First Hard Freeze (28°F): Nov 4 - Nov 10
  • Annual Rainfall: 42-52 inches
  • Common Soils: Silt loam, Clay loam, Limestone-derived

Plant Zone Range (zones 9-11)

9a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 6.58.5

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 Kurrajong in Kentucky

The frost window

Across Kentucky, the last spring hard freeze (28°F) clears between Mar 27 and Apr 2, and the first fall hard freeze lands between Nov 4 and Nov 10 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 216-day window you can count on — up to 228 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

Kentucky runs as cold as USDA zone 6, and no sourced winter-hardiness floor is on record for kurrajong, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether kurrajong is a permanent planting or a replant-every-spring crop for you turns on your own zone within Kentucky; check its hardiness range against that before treating it as long-lived ground.

Timing tuned to sub-state frost dates — Greenup County, not the statewide average.

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.

Growing Season Fit

The zone check says kurrajong does not survive a Kentucky winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Kentucky under protection.

Frost-free days

Kurrajong wants 90+ frost-free days; a typical Kentucky site sees ~221 (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

Kurrajong likes near-neutral soil (pH 6.5-8.5). That's the common-ground band across Kentucky's silt loam and clay loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 7 and 8 — worth knowing before you decide whether a Kentucky soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Kentucky site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Your land, not the state average

Kentucky soil pH runs about 5.5–6.3, and that sits below kurrajong's tolerated 6.5–8.5, so the typical Kentucky parcel needs lime before it will perform. SSURGO maps it swinging by full points parcel to parcel, so your map unit, not the state number, decides whether kurrajong needs lime or sulfur.

Check your parcel → Source: USDA NRCS SSURGO.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Kentucky soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

What Else to Consider for Kurrajong in Kentucky

Zone compatibility tells you about winter cold survival — but Kentucky growers also need to think about:

Heavy clay soils in the Bluegrass region

High humidity promotes fungal diseases

Karst topography creates drainage unpredictability

Growing kurrajong here specifically

Kurrajong wants soil pH 6.5–8.5, but Kentucky's soils run acidic (SSURGO maps a dominant pH near 5.9) — below its range, nutrients lock up and growth stalls.

Test your soil and lime to raise pH into kurrajong's 6.5–8.5 range before planting. How to handle it →

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

Timing shifts within Kentucky

Kentucky isn't one climate. In Greenup County, the last hard freeze (28°F) holds until about Apr 13 — roughly 13 days later than the recorded state median — so plant kurrajong to your county's window, not the statewide date.

Kurrajong needs about 90 days of frost-free season to complete its cycle. Even Greenup County — Kentucky’s shortest season at 195 frost-free days — clears that by 105 days, so season length isn’t the constraint anywhere in Kentucky. What varies is your own parcel.

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"). Kurrajong's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

Kurrajong draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, kurrajong can only work that bloom inside Kentucky's frost window — roughly 221 days, opening after the last 28°F freeze (Mar 27 - Apr 2) and closing at the first (Nov 4 - Nov 10), per NOAA Regional Climate Centers ACIS, 1991-2020.

Kentucky Cooperative Extension

For Kentucky-specific cultivar recommendations, planting calendars, and pest pressure for kurrajong, the canonical source is University of Kentucky Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Common Questions About Growing Kurrajong in Kentucky

When can I plant Kurrajong in Kentucky?

Kentucky's last spring hard freeze (28°F) clears between Mar 27 and Apr 2, and the first fall hard freeze lands between Nov 4 and Nov 10 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Kurrajong, so this page does not state whether it overwinters in Kentucky 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 Kurrajong grown in across Kentucky?

Kentucky spans USDA hardiness zones 6a-7b (USDA ARS PHZM 2023). Kurrajong carries a range of zones 9-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical Kentucky site have?

A typical Kentucky site sees ~221 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Kurrajong needs 90+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Greenup, the freeze-free season runs shorter than the state average, so verify your own county's window.

How should I amend the soil for Kurrajong in Kentucky?

Kurrajong prefers pH 6.5-8.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Kentucky soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.

Will Kurrajong actually grow on my specific land in Kentucky?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores kurrajong 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 Kentucky

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

Three things about your lot that Kentucky kurrajong averages can't show:

Your soil pHYour frost-free days — Kentucky averages 221Your sun & shade

We read public map data around Kentucky — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Kentucky kurrajong average

Explore More

Explore Kentucky county by county

Kentucky carries 120 counties with their own USDA zone — a sample of the growing pages for kurrajong there:

Where else kurrajong grows

Kurrajong's zone band crosses state lines — these are the states closest to Kentucky 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 Kentucky

Kentucky has a growing page for 893 plants — a rotating sample of the rest of the shelf.

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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