Yes — Strong Match
horehound (zones 3-9) covers every zone Kentucky contains (6a-7b), so hardiness is not what limits it anywhere in the state.
Horehound in Kentucky — the short answer
Horehound in Kentucky: hardy in zones 3–9, full sun.
- Plant zones
- 3-9
- NC State Extension Gardener Plant Toolbox
- 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
- Days to maturity
- 90 days
- Growable Ground Plant Database
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.
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 horehound 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 parcel report in seconds — read in full free for your first 14 days
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 horehound overwintering in the ground and coming under cover.
The middle half of 120 counties runs 6.5–7 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 in Kentucky Fits Best
Even within Kentucky's zones 6a-7b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for horehound (USDA PHZM 2023):
Zone Comparison
Horehound Needs
- USDA Zones: 3-9
- Sun: Full SunWe haven't confirmed this against a published source yet.
- Mature size: 2 ft tallWe haven't confirmed this against a published source yet.
- Picking window: ~90 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: HighWe haven't confirmed this against a published source yet.
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 3-9)
Preferred Soil pH
We haven't confirmed this against a published source yet.
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 Horehound 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.
When to start the seed
Those dates are when horehound goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Kentucky's late-side last freeze of Apr 2 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Winter standing
Kentucky runs as cold as USDA zone 6, and no sourced winter-hardiness floor is on record for horehound, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether horehound 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.
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 horehound survives winter here. Whether the season is long enough — and warm enough — is a different question.
Growing degree days
Horehound needs ~800 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~3689 GDD (from PRISM 1991-2020 climate normals), so Kentucky'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
Horehound tolerates a wide pH range (pH 4.5-7.5) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Kentucky. 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 5.5 and 7 — 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, a raised bed lifts the roots above wet ground, or work in compost. pH range, preferred pH and drainage need: We haven't confirmed this against a published source yet.
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.
Before you plant horehound for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before horehound goes in. What follows is Kentucky’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across Kentucky — and how to grow with it.
We checked the federal record across Kentucky — 19,166 documented sites across 7 of the 8 source types we track.
The most significant on record: 219 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Kentucky carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds of imported, lab-tested soil grow well almost anywhere in the meantime.
Sources Checked
across Kentucky
Severity Distribution
across Kentucky
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
- •Near a brownfield, a raised bed of imported, lab-tested soil lowers contact with the ground; it does not remove it.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Horehound 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
What to actually do about these — and the constraints that apply to every Kentucky grower, not just horehound — is covered on the Kentucky growing guide.
Where in Kentucky Horehound Is Zone-Hardy
Horehound is rated for USDA zones 3–9. Every one of Kentucky’s 120 counties sits inside that band — from Anderson County at zone 6b to Lyon County at zone 7b — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.
Across those 120 counties Kentucky’s winter-low ladder runs from zone 6b in Anderson County to zone 7b in Lyon County — 1 USDA zone of spread, which is 10°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. Greenup County holds its last hard freeze (28°F) until about Apr 13, while Livingston County is clear by Mar 18 — 26 days apart. Set horehound 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". Horehound’s zone 3–9 band: NC State Extension Gardener Plant Toolbox. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Horehound draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, horehound 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. Pollinator value: We haven't confirmed this against a published source yet.
Kentucky Cooperative Extension
For Kentucky-specific cultivar recommendations, planting calendars, and pest pressure for horehound, the canonical source is University of Kentucky Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Horehound native to Kentucky?
No — the USDA PLANTS Database lists Horehound as introduced rather than native in the Lower 48, so it is not part of Kentucky's native flora. It grows here as a garden plant; pairing it with a few Kentucky natives keeps local pollinators fed too.
Looking for plants that belong here? The Kentucky growing guide lists plants that USDA PLANTS records growing in Kentucky and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.
State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.
Common Questions About Growing Horehound in Kentucky
When can I plant Horehound 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 Horehound, 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 Horehound grown in across Kentucky?
Kentucky spans USDA hardiness zones 6a-7b (USDA ARS PHZM 2023). Horehound carries a range of zones 3-9, 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). Horehound 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 Horehound native to Kentucky?
No — the USDA PLANTS Database lists Horehound as introduced rather than native in the Lower 48, so it is not part of Kentucky's native flora. It grows here as a garden plant; pairing it with a few Kentucky natives keeps local pollinators fed too.
How should I amend the soil for Horehound in Kentucky?
Horehound tolerates pH 4.5-7.5 and well (dry spells) drainage. We haven't confirmed this against a published source yet. That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Kentucky site — amend for drainage and organic matter first.
Will Horehound actually grow on my specific land in Kentucky?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores horehound against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Kentucky
State-level data is a sketch. Your Growable Ground report scores horehound against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Kentucky horehound averages can't show:
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 horehound average
Explore More
Growing guides for horehound
Explore Kentucky county by county
Kentucky carries 120 counties with their own USDA zone — a sample of the growing pages for horehound there:
Where else horehound grows
Horehound'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 889 plants — a rotating sample of the rest of the shelf.
Last updated: