Yes — Strong Match
Roman chamomile (zones 3-9) covers every zone Wyoming contains (3b-6a), so hardiness is not what limits it anywhere in the state.
Roman Chamomile in Wyoming — the short answer
Roman Chamomile in Wyoming: hardy in zones 3–9, full sun.
- Plant zones
- 3-9
- Not verified — NC State Extension Gardener Plant Toolbox lists zones 4a–9b
- Wyoming zones
- 3b-6a
- USDA PHZM 2023
- Frost window
- May 4 - May 13 – Sep 30 - Oct 7
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 79 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.
Wyoming spans zones 3b-6a, 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 roman chamomile 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
Wyoming is not one climate
Wyoming’s winter-low ladder runs across 23 counties, from zone 4.5 in Albany County to zone 5.5 in Uinta County. That is 10°F between the two counties’ average coldest night — the difference between roman chamomile overwintering in the ground and coming under cover.
The middle half of 23 counties runs 4.5–5 zones, with a median of 5 zones — a 1-zone span end to end.
Measured across 23 Wyoming 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 Wyoming Fits Best
Even within Wyoming's zones 3b-6a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for roman chamomile (USDA PHZM 2023):
Zone Comparison
Roman Chamomile Needs
- USDA Zones: 3-9
- Sun: Full Sun
- Mature size: 6 in tall
- Picking window: ~60 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: MediumWe haven't confirmed this against a published source yet.
Wyoming Has
- USDA Zones: 3b-6a
- Last Hard Freeze (28°F): May 4 - May 13
- First Hard Freeze (28°F): Sep 30 - Oct 7
- Annual Rainfall: 6-20 inches
- Common Soils: Sandy loam, Clay, Alkaline
Plant Zone Range (zones 3-9)
Preferred Soil pH
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 Roman Chamomile in Wyoming
The frost window
Across Wyoming, the last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 140-day window you can count on — up to 156 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 tenderness
Roman Chamomile is frost-tender — FAO ECOCROP puts its killing temperature at 32°F — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Those dates are when roman chamomile goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Wyoming's late-side last freeze of May 13 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Grown as an annual here
Roman Chamomile is a true perennial in its home range — it overwinters from USDA zone 4 and warmer (NC State Extension Gardener Plant Toolbox) — but Wyoming runs as cold as zone 3, so it is killed back each winter and replanted each spring. Treat it on the season schedule above, not as a permanent planting: there is no fall establishment window for it here.
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 roman chamomile survives winter here. Whether the season is long enough — and warm enough — is a different question.
Growing degree days
Roman Chamomile needs ~700 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~1866 GDD (from PRISM 1991-2020 climate normals), so Wyoming'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
Roman Chamomile likes near-neutral soil (pH 5.5-8). That's the common-ground band across Wyoming's sandy loam and clay — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a Wyoming soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Wyoming site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost. 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. Wyoming soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant roman chamomile 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 roman chamomile goes in. What follows is Wyoming’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 Wyoming — and how to grow with it.
We checked the federal record across Wyoming — 4,526 documented sites across 7 of the 8 source types we track.
The most significant on record: 64 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Wyoming 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 Wyoming
Severity Distribution
across Wyoming
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •TRI facilities report what they release. Check the wind — downwind beds catch more of it.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Roman Chamomile in Wyoming
Zone compatibility tells you about winter cold survival — but Wyoming growers also need to think about:
Extremely short growing season (60-90 frost-free days)
Very low rainfall requires irrigation
Persistent high winds desiccate and damage plants
What to actually do about these — and the constraints that apply to every Wyoming grower, not just roman chamomile — is covered on the Wyoming growing guide.
Where in Wyoming Roman Chamomile Is Zone-Hardy
Roman Chamomile is rated for USDA zones 3–9. Every one of Wyoming’s 23 counties sits inside that band — from Albany County at zone 4b to Uinta County at zone 5b — 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 23 counties Wyoming’s winter-low ladder runs from zone 4b in Albany County to zone 5b in Uinta 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. Teton County holds its last hard freeze (28°F) until about Jun 16, while Big Horn County is clear by Apr 26 — 51 days apart. Set roman chamomile 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". Roman Chamomile’s zone 3–9 band: Not verified — NC State Extension Gardener Plant Toolbox lists zones 4a–9b. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Roman Chamomile draws honeybees and native bees (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, roman chamomile can only work that bloom inside Wyoming's frost window — roughly 151 days, opening after the last 28°F freeze (May 4 - May 13) and closing at the first (Sep 30 - Oct 7), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
Wyoming Cooperative Extension
For Wyoming-specific cultivar recommendations, planting calendars, and pest pressure for roman chamomile, the canonical source is University of Wyoming Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Roman Chamomile native to Wyoming?
No — the USDA PLANTS Database lists Roman Chamomile as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.
Looking for plants that belong here? The Wyoming growing guide lists plants that USDA PLANTS records growing in Wyoming 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 Roman Chamomile in Wyoming
When can I plant Roman Chamomile in Wyoming?
Wyoming's last spring hard freeze (28°F) clears between May 4 and May 13, and the first fall hard freeze lands between Sep 30 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Roman Chamomile overwinters only from USDA zone 4 and warmer, and Wyoming runs as cold as zone 3, so it is grown as an annual here — plant it after the last hard freeze, two to three weeks later for tender stock, and expect to replant next spring rather than establishing it for the long term.
What hardiness zone is Roman Chamomile grown in across Wyoming?
Wyoming spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Roman Chamomile 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 Wyoming site have?
A typical Wyoming site sees ~151 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Roman Chamomile needs 180+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Roman Chamomile native to Wyoming?
No — the USDA PLANTS Database lists Roman Chamomile as introduced rather than native in the Lower 48, so it is not part of Wyoming's native flora. It grows here as a garden plant; pairing it with a few Wyoming natives keeps local pollinators fed too.
How should I amend the soil for Roman Chamomile in Wyoming?
Roman Chamomile prefers pH 5.5-8 and well (dry spells) drainage. We haven't confirmed this against a published source yet. That sits in the common-ground band across Wyoming soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Roman Chamomile actually grow on my specific land in Wyoming?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores roman chamomile 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 Wyoming
State-level data is a sketch. Your Growable Ground report scores roman chamomile against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Wyoming roman chamomile averages can't show:
We read public map data around Wyoming — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Wyoming roman chamomile average
Explore More
Growing guides for roman chamomile
Explore Wyoming county by county
Wyoming carries 23 counties with their own USDA zone — a sample of the growing pages for roman chamomile there:
Where else roman chamomile grows
Roman Chamomile's zone band crosses state lines — these are the states closest to Wyoming 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 Wyoming
Wyoming has a growing page for 807 plants — a rotating sample of the rest of the shelf.
Last updated: