Conditional — Some Areas
sweet autumn clematis (zones 5-9) reaches only part of Minnesota (3a-5a): zone 5 are in range, so where you are in the state decides it.
Your yard isn't the whole zone.
Minnesota spans zones 3a-5a, 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 sweet autumn clematis against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Sweet Autumn Clematis Needs
- USDA Zones: 5-9
- Frost-Free Days: 150+
- Sun: Full Sun
- Mature size: 25 ft tall
- Drought tolerance: Medium
Minnesota Has
- USDA Zones: 3a-5a
- Last Hard Freeze (28°F): Apr 19 - Apr 30
- First Hard Freeze (28°F): Oct 10 - Oct 17
- Annual Rainfall: 19-34 inches
- Common Soils: Prairie loam, Clay, Sandy outwash
Plant Zone Range (zones 5-9)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Sweet Autumn Clematis in Minnesota
The frost window
Across Minnesota, the last spring hard freeze (28°F) clears between Apr 19 and Apr 30, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 163-day window you can count on — up to 181 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.
Winter standing
Minnesota runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for sweet autumn clematis, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether sweet autumn clematis is a permanent planting or a replant-every-spring crop for you turns on your own zone within Minnesota; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Lake County, not the statewide average.
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.
Growing Season Fit
The zone check says sweet autumn clematis survives winter in part of Minnesota, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Sweet Autumn Clematis wants 150+ frost-free days; a typical Minnesota site sees ~174 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.
Growing degree days
Sweet Autumn Clematis needs ~2000 GDD (base 50°F) to ripen. The state median runs ~1920 GDD (from PRISM 1991-2020 climate normals), so Minnesota's typical season runs short on heat — pick a south-facing site and consider season extension.
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
Sweet Autumn Clematis likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Minnesota's prairie loam and clay — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.5 and 7.5 — worth knowing before you decide whether a Minnesota soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Minnesota site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Minnesota's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for sweet autumn clematis is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how sweet autumn clematis performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Minnesota soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Sweet Autumn Clematis in Minnesota — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 5-9 (USDA PLANTS Database)
- State Zones: 3a-5a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 19 - Apr 30 to Oct 10 - Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Sweet Autumn Clematis in Minnesota
Zone compatibility tells you about winter cold survival — but Minnesota growers also need to think about:
Extreme cold (zone 3a: -40F) limits many species
Short growing season (100-140 frost-free days)
Heavy clay soils in the Red River Valley
Growing sweet autumn clematis here specifically
Sweet Autumn Clematis wants pH 5.5–7.5 and rates to USDA zones 5–9, but Minnesota's soils are dominantly loam — the fit is decided by your parcel's own map unit, not the state average.
Match sweet autumn clematis to your parcel's SSURGO map unit — test pH and texture, and amend toward its 5.5–7.5 range. How to handle it →
What to actually do about these — and the constraints that apply to every Minnesota grower, not just sweet autumn clematis — is covered on the Minnesota growing guide.
Timing shifts within Minnesota
Minnesota isn't one climate. In Lake County, the last hard freeze (28°F) holds until about May 14 — roughly 23 days later than the recorded state median — so plant sweet autumn clematis to your county's window, not the statewide date.
Sweet Autumn Clematis needs about 150 days of frost-free season to complete its cycle. 84 of Minnesota’s 87 counties give it that outright. The tightest that does is Lake of the Woods County at 151 frost-free days — 1 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Minnesota’s 87 counties the frost-free season runs from 137 days in Lake County to 199 days in Ramsey County — a spread of 62 days, which is why a single statewide planting date misleads. The median Minnesota county sees 174 frost-free days, leaving sweet autumn clematis about 24 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"). Sweet Autumn Clematis's 150-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in Minnesota Fits Best
Even within Minnesota's zones 3a-5a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for sweet autumn clematis (USDA PHZM 2023):
Pollinator + Wildlife Value
Sweet Autumn Clematis draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, sweet autumn clematis can only work that bloom inside Minnesota's frost window — roughly 174 days, opening after the last 28°F freeze (Apr 19 - Apr 30) and closing at the first (Oct 10 - Oct 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Sweet Autumn Clematis
Sweet Autumn Clematis is listed as toxic to dogs, cats (all) at a mild level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
Minnesota Cooperative Extension
For Minnesota-specific cultivar recommendations, planting calendars, and pest pressure for sweet autumn clematis, the canonical source is University of Minnesota Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sweet Autumn Clematis native to Minnesota?
No — the USDA PLANTS Database lists Sweet Autumn Clematis as introduced rather than native in the Lower 48, so it is not part of Minnesota's native flora. It grows here as a garden plant; pairing it with a few Minnesota natives keeps local pollinators fed too.
Looking for plants that belong here? The Minnesota 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 Sweet Autumn Clematis in Minnesota
When can I plant Sweet Autumn Clematis in Minnesota?
Minnesota's last spring hard freeze (28°F) clears between Apr 19 and Apr 30, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Sweet Autumn Clematis, so this page does not state whether it overwinters in Minnesota 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 Sweet Autumn Clematis grown in across Minnesota?
Minnesota spans USDA hardiness zones 3a-5a (USDA ARS PHZM 2023). Sweet Autumn Clematis 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 Minnesota site have?
A typical Minnesota site sees ~174 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Sweet Autumn Clematis 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 Lake, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Sweet Autumn Clematis native to Minnesota?
No — the USDA PLANTS Database lists Sweet Autumn Clematis as introduced rather than native in the Lower 48, so it is not part of Minnesota's native flora. It grows here as a garden plant; pairing it with a few Minnesota natives keeps local pollinators fed too.
How should I amend the soil for Sweet Autumn Clematis in Minnesota?
Sweet Autumn Clematis prefers pH 5.5-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across Minnesota soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Sweet Autumn Clematis actually grow on my specific land in Minnesota?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores sweet autumn clematis 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 Minnesota
State-level data is a sketch. Your Growable Ground report scores sweet autumn clematis against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Minnesota sweet autumn clematis averages can't show:
We read public map data around Minnesota — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Minnesota sweet autumn clematis average
Explore More
Growing guides for sweet autumn clematis
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
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