Generally — Most Areas
hollyhock (zones 5-9) suits most of Montana (3a-6b) — zones 5-6 are in range, and the rest of the state is the exception.
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 hollyhock 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
Zone Comparison
Hollyhock Needs
- USDA Zones: 5-9
- Sun: Full Sun
- Mature size: 6 ft tall
- Picking window: ~45 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 5-9)
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Hollyhock 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.
When to start the seed
Those dates are when hollyhock 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.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Soil + Drainage Fit
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 and drainage requirements from USDA PLANTS Database. Montana soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Hollyhock in Montana — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 5-9 (USDA PLANTS Database)
- State Zones: 3a-6b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about May 2 - May 13 to Sep 28 - Oct 7 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Hollyhock 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 hollyhock — is covered on the Montana growing guide.
Where in Montana Hollyhock Is Zone-Hardy
Hollyhock is rated for USDA zones 5–9. 17 of Montana’s 56 counties fall inside that band. The coldest that does is Beaverhead County at zone 5a. 39 counties sit below the plant’s zone 5 floor, where an unprotected plant is relying on snow cover and a mild year. Where you are in Montana decides this one.
Across those 56 counties Montana’s winter-low ladder runs from zone 3b in Daniels County to zone 6a in Sanders County — 2.5 USDA zones of spread, which is 25°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. Deer Lodge County holds its last hard freeze (28°F) until about Jun 21, while Petroleum County is clear by Apr 25 — 57 days apart. Set hollyhock 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". Hollyhock’s zone 5–9 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
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 hollyhock (USDA PHZM 2023):
Pollinator + Wildlife Value
Hollyhock draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, hollyhock 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 hollyhock, the canonical source is Montana State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Hollyhock native to Montana?
No — the USDA PLANTS Database lists Hollyhock 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 Hollyhock in Montana
When can I plant Hollyhock 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). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
What hardiness zone is Hollyhock grown in across Montana?
Montana spans USDA hardiness zones 3a-6b (USDA ARS PHZM 2023). Hollyhock carries a range of zones 5-9, 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). Hollyhock 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 Hollyhock native to Montana?
No — the USDA PLANTS Database lists Hollyhock 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.
Will Hollyhock actually grow on my specific land in Montana?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores hollyhock 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 hollyhock against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Montana hollyhock 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 hollyhock average
Last updated: