Yes — Strong Match
St. Johns wort (zones 3-8) covers every zone Kansas contains (5b-7a), so hardiness is not what limits it anywhere in the state.
St Johns Wort in Kansas — the short answer
St Johns Wort in Kansas: hardy in zones 3–8, full sun.
- Plant zones
- 3-8
- NC State Extension Gardener Plant Toolbox
- Kansas zones
- 5b-7a
- USDA PHZM 2023
- Frost window
- Apr 1 - Apr 12 – Oct 25 - Nov 3
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 177 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 120 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.
Kansas spans zones 5b-7a, 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 st johns wort 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
Kansas is not one climate
Kansas’s winter-low ladder runs across 105 counties, from zone 6 in Atchison County to zone 7 in Wilson County. That is 10°F between the two counties’ average coldest night — the difference between st johns wort overwintering in the ground and coming under cover.
The middle half of 105 counties runs 6–6.5 zones, with a median of 6.5 zones — a 1-zone span end to end.
Measured across 105 Kansas 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 Kansas Fits Best
Even within Kansas's zones 5b-7a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for st johns wort (USDA PHZM 2023):
Zone Comparison
St Johns Wort Needs
- USDA Zones: 3-8
- Sun: Full SunWe haven't confirmed this against a published source yet.
- Mature size: 3 ft tallWe haven't confirmed this against a published source yet.
- Picking window: ~30 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: MediumWe haven't confirmed this against a published source yet.
Kansas Has
- USDA Zones: 5b-7a
- Last Hard Freeze (28°F): Apr 1 - Apr 12
- First Hard Freeze (28°F): Oct 25 - Nov 3
- Annual Rainfall: 16-42 inches
- Common Soils: Prairie loam, Silt loam, Clay
Plant Zone Range (zones 3-8)
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 St Johns Wort in Kansas
The frost window
Across Kansas, the last spring hard freeze (28°F) clears between Apr 1 and Apr 12, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 196-day window you can count on — up to 216 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 st johns wort goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Kansas's late-side last freeze of Apr 12 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Winter standing
Kansas runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for st johns wort, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether st johns wort is a permanent planting or a replant-every-spring crop for you turns on your own zone within Kansas; 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 st johns wort survives winter here. Whether the season is long enough — and warm enough — is a different question.
Growing degree days
St Johns Wort needs ~700 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~3821 GDD (from PRISM 1991-2020 climate normals), so Kansas'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
St Johns Wort tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Kansas. 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 Kansas soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Kansas 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. Kansas soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant st johns wort 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 st johns wort goes in. What follows is Kansas’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 Kansas — and how to grow with it.
We checked the federal record across Kansas — 11,979 documented sites across 7 of the 8 source types we track.
The most significant on record: 146 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Kansas 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 Kansas
Severity Distribution
across Kansas
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kansas, two things run higher than the national average across Kansas — CAFO (485 sites) and Brownfields (908 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Brownfields: Brownfield sites are former commercial or industrial properties that EPA’s Brownfields program (ACRES) has assessed or funded cleanup on.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Contact the EPA Brownfields program or the state cleanup agency for this site’s actual assessment/remediation status — ACRES itself does not publish one we can read per site.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for St Johns Wort in Kansas
Zone compatibility tells you about winter cold survival — but Kansas growers also need to think about:
Low rainfall in western KS requires irrigation
Extreme wind and hail during severe storm season
Hot dry summers with 100F+ days
What to actually do about these — and the constraints that apply to every Kansas grower, not just st johns wort — is covered on the Kansas growing guide.
Where in Kansas St Johns Wort Is Zone-Hardy
St Johns Wort is rated for USDA zones 3–8. Every one of Kansas’s 105 counties sits inside that band — from Atchison County at zone 6a to Wilson County at zone 7a — 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 105 counties Kansas’s winter-low ladder runs from zone 6a in Atchison County to zone 7a in Wilson 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. Rawlins County holds its last hard freeze (28°F) until about Apr 23, while Cherokee County is clear by Mar 24 — 30 days apart. Set st johns wort 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". St Johns Wort’s zone 3–8 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
St Johns Wort draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, st johns wort can only work that bloom inside Kansas's frost window — roughly 208 days, opening after the last 28°F freeze (Apr 1 - Apr 12) and closing at the first (Oct 25 - Nov 3), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
Kansas Cooperative Extension
For Kansas-specific cultivar recommendations, planting calendars, and pest pressure for st johns wort, the canonical source is K-State Research and Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is St Johns Wort native to Kansas?
No — the USDA PLANTS Database lists St Johns Wort as introduced rather than native in the Lower 48, so it is not part of Kansas's native flora. It grows here as a garden plant; pairing it with a few Kansas natives keeps local pollinators fed too.
Looking for plants that belong here? The Kansas growing guide lists plants that USDA PLANTS records growing in Kansas 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 St Johns Wort in Kansas
When can I plant St Johns Wort in Kansas?
Kansas's last spring hard freeze (28°F) clears between Apr 1 and Apr 12, and the first fall hard freeze lands between Oct 25 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for St Johns Wort, so this page does not state whether it overwinters in Kansas 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 St Johns Wort grown in across Kansas?
Kansas spans USDA hardiness zones 5b-7a (USDA ARS PHZM 2023). St Johns Wort carries a range of zones 3-8, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Kansas site have?
A typical Kansas site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). St Johns Wort 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.
Is St Johns Wort native to Kansas?
No — the USDA PLANTS Database lists St Johns Wort as introduced rather than native in the Lower 48, so it is not part of Kansas's native flora. It grows here as a garden plant; pairing it with a few Kansas natives keeps local pollinators fed too.
How should I amend the soil for St Johns Wort in Kansas?
St Johns Wort tolerates pH 5-8 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 Kansas site — amend for drainage and organic matter first.
Will St Johns Wort actually grow on my specific land in Kansas?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores st johns wort 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 Kansas
State-level data is a sketch. Your Growable Ground report scores st johns wort against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Kansas st johns wort averages can't show:
We read public map data around Kansas — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kansas st johns wort average
Explore More
Growing guides for st johns wort
Explore Kansas county by county
Kansas carries 105 counties with their own USDA zone — a sample of the growing pages for st johns wort there:
Where else st johns wort grows
St Johns Wort's zone band crosses state lines — these are the states closest to Kansas 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 Kansas
Kansas has a growing page for 889 plants — a rotating sample of the rest of the shelf.
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