Generally — Most Areas
sweet autumn clematis (zones 5-9) suits most of Wisconsin (3b-6a) — zones 5-6 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
Wisconsin 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 sweet autumn clematis 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 full report in seconds
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
Wisconsin Has
- USDA Zones: 3b-6a
- Last Hard Freeze (28°F): Apr 17 - May 2
- First Hard Freeze (28°F): Oct 9 - Oct 21
- Annual Rainfall: 28-34 inches
- Common Soils: Silt loam, Clay loam, 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 Wisconsin
The frost window
Across Wisconsin, the last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 187 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
Wisconsin 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 Wisconsin; check its hardiness range against that before treating it as long-lived ground.
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 Wisconsin, 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 Wisconsin site sees ~173 (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 ~2102 GDD (from PRISM 1991-2020 climate normals), so Wisconsin sits right at the threshold — pay attention to siting and microclimate.
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 Wisconsin's silt loam and clay loam — 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 Wisconsin soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Wisconsin 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. Wisconsin soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Sweet Autumn Clematis in Wisconsin — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 5-9 (USDA PLANTS Database)
- State Zones: 3b-6a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 17 - May 2 to Oct 9 - Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Sweet Autumn Clematis in Wisconsin
Zone compatibility tells you about winter cold survival — but Wisconsin growers also need to think about:
Cold winters (-30F in northern WI)
Short growing season (110-140 frost-free days)
Sandy central soils drain too quickly
What to actually do about these — and the constraints that apply to every Wisconsin grower, not just sweet autumn clematis — is covered on the Wisconsin growing guide.
Timing shifts within Wisconsin
Sweet Autumn Clematis needs about 150 days of frost-free season to complete its cycle. 67 of Wisconsin’s 72 counties give it that outright. The tightest that does is Iron County at 150 frost-free days — 0 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Wisconsin’s 72 counties the frost-free season runs from 140 days in Florence County to 217 days in Milwaukee County — a spread of 77 days, which is why a single statewide planting date misleads. The median Wisconsin county sees 173 frost-free days, leaving sweet autumn clematis about 23 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 Wisconsin Fits Best
Even within Wisconsin's zones 3b-6a, 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 Wisconsin's frost window — roughly 173 days, opening after the last 28°F freeze (Apr 17 - May 2) and closing at the first (Oct 9 - Oct 21), per NOAA Regional Climate Centers ACIS, 1991-2020.
Wisconsin Cooperative Extension
For Wisconsin-specific cultivar recommendations, planting calendars, and pest pressure for sweet autumn clematis, the canonical source is UW–Madison Division of Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Sweet Autumn Clematis native to Wisconsin?
No — the USDA PLANTS Database lists Sweet Autumn Clematis as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.
Looking for plants that belong here? The Wisconsin 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 Wisconsin
When can I plant Sweet Autumn Clematis in Wisconsin?
Wisconsin's last spring hard freeze (28°F) clears between Apr 17 and May 2, and the first fall hard freeze lands between Oct 9 and Oct 21 (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 Wisconsin 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 Wisconsin?
Wisconsin spans USDA hardiness zones 3b-6a (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 Wisconsin site have?
A typical Wisconsin site sees ~173 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.
Is Sweet Autumn Clematis native to Wisconsin?
No — the USDA PLANTS Database lists Sweet Autumn Clematis as introduced rather than native in the Lower 48, so it is not part of Wisconsin's native flora. It grows here as a garden plant; pairing it with a few Wisconsin natives keeps local pollinators fed too.
How should I amend the soil for Sweet Autumn Clematis in Wisconsin?
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 Wisconsin 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 Wisconsin?
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 Wisconsin
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 Wisconsin sweet autumn clematis averages can't show:
We read public map data around Wisconsin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Wisconsin sweet autumn clematis average
Explore More
Growing guides for sweet autumn clematis
Last updated: