Yes — Strong Match
Roman chamomile (zones 3-9) covers every zone Montana contains (3a-6b), so hardiness is not what limits it anywhere in the state.
Roman Chamomile in Montana — the short answer
Roman Chamomile in Montana: hardy in zones 3–9, full sun, against a state median of ~151 frost-free days.
- Plant zones
- 3-9
- 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
- Montana zones
- 3a-6b
- USDA PHZM 2023
- Frost window
- May 2 - May 13 – Sep 28 - Oct 7
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 59 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.
Montana spans zones 3a-6b, 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.
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Montana is not one climate
Montana’s winter-low ladder runs across 56 counties, from zone 3.5 in Daniels County to zone 6 in Sanders County. That is 25°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 56 counties runs 4–5 zones, with a median of 4.5 zones — a 2.5-zone span end to end.
Measured across 56 Montana 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 Montana Fits Best
Even within Montana's zones 3a-6b, 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
- Frost-Free Days: 180+
- Sun: Full Sun
- Mature size: 6 in tall
- Picking window: ~60 days of harvest
- Drought tolerance: Medium
Montana Has
- USDA Zones: 3a-6b
- Last Hard Freeze (28°F): May 2 - May 13
- First Hard Freeze (28°F): Sep 28 - Oct 7
- Annual Rainfall: 10-20 inches
- Common Soils: Sandy loam, Clay, Glacial till
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 Montana
The frost window
Across Montana, the last spring hard freeze (28°F) clears between May 2 and May 13, and the first fall hard freeze lands between Sep 28 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 138-day window you can count on — up to 158 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 Montana'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; Missouri Botanical Garden Plant Finder) — but Montana 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.
Frost-free days
Roman Chamomile wants 180+ frost-free days; a typical Montana site sees ~151 (NOAA Regional Climate Centers ACIS, 1991-2020) — 29 days short of what it needs. A typical Montana season does not carry this crop to harvest outdoors, and a gap that size is not one an earlier sowing date or a faster cultivar closes; growing it here means growing it under cover.
Growing degree days
Roman Chamomile needs ~700 GDD (base 50°F) to ripen. The state median runs ~1769 GDD (from PRISM 1991-2020 climate normals), so Montana'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 Montana'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 Montana soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Montana site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
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. Montana 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 Montana’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 Montana — and how to grow with it.
We checked the federal record across Montana — 22,453 documented sites across 8 of the 9 source types we track.
The most significant on record: 124 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Montana 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 with clean imported soil grow well almost anywhere in the meantime.
Sources Checked
across Montana
Severity Distribution
across Montana
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Montana, two things run higher than the national average across Montana — Mining (4,319 sites) and Nitrate (10,260 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What Else to Consider for Roman Chamomile in Montana
Zone compatibility tells you about winter cold survival — but Montana growers also need to think about:
Very short growing season (60-100 frost-free days)
Low rainfall requires irrigation in most areas
Extreme winter cold (-40F possible)
What to actually do about these — and the constraints that apply to every Montana grower, not just roman chamomile — is covered on the Montana growing guide.
Timing shifts within Montana
Roman Chamomile needs about 180 days of frost-free season to complete its cycle. No Montana county gives it that outdoors: even Petroleum County, the state’s longest season at 170 frost-free days, falls 10 days short — so it needs transplants, a short-season variety, or covered growing.
Across Montana’s 56 counties the frost-free season runs from 59 days in Deer Lodge County to 170 days in Petroleum County — a spread of 111 days, which is why a single statewide planting date misleads. The median Montana county sees 151 frost-free days, which is 29 days short of what roman chamomile needs — so on a typical Montana parcel this is a transplant-or-protect crop, not a direct-sow one.
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"). Roman Chamomile's 180-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
Roman Chamomile draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, roman chamomile can only work that bloom inside Montana's frost window — roughly 151 days, opening after the last 28°F freeze (May 2 - May 13) and closing at the first (Sep 28 - Oct 7), per NOAA Regional Climate Centers ACIS, 1991-2020.
Montana Cooperative Extension
For Montana-specific cultivar recommendations, planting calendars, and pest pressure for roman chamomile, the canonical source is Montana State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Roman Chamomile native to Montana?
No — the USDA PLANTS Database lists Roman Chamomile as introduced rather than native in the Lower 48, so it is not part of Montana's native flora. It grows here as a garden plant; pairing it with a few Montana natives keeps local pollinators fed too.
Looking for plants that belong here? The Montana growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Roman Chamomile in Montana
When can I plant Roman Chamomile in Montana?
Montana's last spring hard freeze (28°F) clears between May 2 and May 13, and the first fall hard freeze lands between Sep 28 and Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020). Roman Chamomile overwinters only from USDA zone 4 and warmer, and Montana 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 Montana?
Montana spans USDA hardiness zones 3a-6b (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 Montana site have?
A typical Montana 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 Montana?
No — the USDA PLANTS Database lists Roman Chamomile as introduced rather than native in the Lower 48, so it is not part of Montana's native flora. It grows here as a garden plant; pairing it with a few Montana natives keeps local pollinators fed too.
How should I amend the soil for Roman Chamomile in Montana?
Roman Chamomile prefers pH 5.5-8 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Montana 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 Montana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores roman chamomile against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Montana
State-level data is a sketch. Your Growable Ground report scores roman chamomile against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Montana roman chamomile averages can't show:
We read public map data around Montana — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Montana roman chamomile average
Explore More
Growing guides for roman chamomile
Explore Montana county by county
Montana carries 56 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 Montana 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 Montana
Montana has a growing page for 747 plants — a rotating sample of the rest of the shelf.
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