Generally — Most Areas
foxglove (zones 4-8) suits most of Montana (3a-6b) — zones 4-6 are in range, and the rest of the state is the exception.
Foxglove in Montana — the short answer
Foxglove in Montana: hardy in zones 4–8, full sun, against a state median of ~151 frost-free days.
- Plant zones
- 4-8
- 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
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 has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score foxglove against your land's actual soil, sun, and frost.
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
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 foxglove 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
Foxglove is rated for zones 4–8 — a cold floor USDA puts at -30 to -20°F. Against Montana’s 56 counties that band holds in 53 of them, and the line runs at Blaine County (zone 4a), the coldest county still inside it.
Inside zones 4–8
53 counties
- Carter County · zone 4a
- Chouteau County · zone 4a
- Dawson County · zone 4a
3 of 53 shown
Below the zone 4 floor
3 counties
- Daniels County · zone 3b
- Roosevelt County · zone 3b
- Sheridan County · zone 3b
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.
Even within Montana's zones 3a-6b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for foxglove (USDA PHZM 2023):
Zone Comparison
Foxglove Needs
- USDA Zones: 4-8
- Frost-Free Days: 150+
- Sun: Full Sun
- Mature size: 4 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Low
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 4-8)
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 Foxglove 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
Foxglove 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 foxglove 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.
Timing tuned to sub-state frost dates — Deer Lodge 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 foxglove survives winter in part of Montana, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Foxglove wants 150+ frost-free days; a typical Montana site sees ~151 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a tight window — use transplants and pick early-maturing cultivars.
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
Foxglove tolerates a wide pH range (pH 4.5-8.3) — 3.8 units, acid ground through alkaline — so soil acidity is rarely what limits it in Montana. 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 6.5 — 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), excessive (dry/moderately dry). If your Montana site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Montana's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Foxglove needs about 19 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how foxglove performs.
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. Montana soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Foxglove 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)
Growing foxglove here specifically
Foxglove sends medium roots and rates to zones 4–8, but much of Montana sits on slow-draining, restrictive ground (SSURGO hydrologic group D) that forks and stunts them.
Loosen a deep, stone-free bed for foxglove and break any compacted or hardpan layer before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Montana grower, not just foxglove — is covered on the Montana growing guide.
Timing shifts within Montana
Montana isn't one climate. In Deer Lodge County, the last hard freeze (28°F) holds until about Jun 21 — roughly 47 days later than the recorded state median — so plant foxglove to your county's window, not the statewide date.
Foxglove needs about 150 days of frost-free season to complete its cycle. 31 of Montana’s 56 counties give it that outright. The tightest that does is Carter County at 150 frost-free days — 0 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
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, leaving foxglove about 1 days of slack on a typical parcel — room for a second sowing where the season runs long.
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"). Foxglove's 150-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
Foxglove draws honeybees, native bees, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, foxglove 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. Deer pressure is meaningful across much of Montana; foxglove is listed as deer-resistant (USDA PLANTS Database), which makes it a safer pick for unfenced sites. Our deer & wildlife guide carries the full deer-resistant list and how to protect the rest.
Good to Know Before You Plant Foxglove
Foxglove is listed as toxic to dogs, cats, horses (all) at a lethal level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Montana this is a one-season plant and the first hard freeze (Sep 28 - Oct 7) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Foxglove Varieties for Montana
Montana publishes no state variety trial for foxglove, so we won't invent a "best for Montana" list. Choose types rated to your USDA hardiness zone (3a-6b), and confirm winter survival and drainage against your own parcel.
Montana Cooperative Extension
For Montana-specific cultivar recommendations, planting calendars, and pest pressure for foxglove, the canonical source is Montana State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Foxglove native to Montana?
No — the USDA PLANTS Database lists Foxglove 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 Foxglove in Montana
When can I plant Foxglove 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). Foxglove is frost-tender — its killing temperature is 32°F (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
What hardiness zone is Foxglove grown in across Montana?
Montana spans USDA hardiness zones 3a-6b (USDA ARS PHZM 2023). Foxglove carries a range of zones 4-8, 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). Foxglove needs 150+ 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 Deer Lodge, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Foxglove native to Montana?
No — the USDA PLANTS Database lists Foxglove 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 Foxglove in Montana?
Foxglove tolerates pH 4.5-8.3 and well (dry spells), excessive (dry/moderately dry) drainage (FAO ECOCROP). That is a 3.8-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Montana site — amend for drainage and organic matter first.
Will Foxglove actually grow on my specific land in Montana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores foxglove 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 foxglove against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Montana foxglove 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 foxglove average
Explore More
Growing guides for foxglove
Explore Montana county by county
Montana carries 56 counties with their own USDA zone — a sample of the growing pages for foxglove there:
Where else foxglove grows
Foxglove'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.
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
Last updated: