Unlikely — Zone Mismatch
tea (zones 7-9) does not overlap with Wisconsin's zone range (3b-6a). Growing outdoors is unlikely without significant protection.
One zone short — what would close it
Tea is hardy to zone 7, and the warmest ground in Wisconsin is zone 6 — 1 zone short. Planted in open ground it will not survive a Wisconsin winter. To grow it here, grow tea in a hoop house or unheated greenhouse — its modeled 1.5-zone lift covers this gap.
A hoop house or unheated greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 7-9 (plant) against 3-6 (Wisconsin). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['hoop_house'] (+1.5 zones) via api/fast_sections.py Unlock Engine v2.
Tea in Wisconsin — the short answer
Tea in Wisconsin: hardy in zones 7–9, full sun, against a state median of ~173 frost-free days.
- Plant zones
- 7-9
- 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
- Wisconsin zones
- 3b-6a
- USDA PHZM 2023
- Frost window
- Apr 17 - May 2 – Oct 9 - Oct 21
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 140 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.
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 tea 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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Wisconsin is not one climate
Wisconsin’s winter-low ladder runs across 72 counties, from zone 4 in Bayfield County to zone 6 in Racine County. That is 20°F between the two counties’ average coldest night — the difference between tea overwintering in the ground and coming under cover.
The middle half of 72 counties runs 4.5–5 zones, with a median of 4.5 zones — a 2-zone span end to end.
Measured across 72 Wisconsin 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 Tea Stands in Wisconsin
Tea is rated for zones 7–9 — a cold floor USDA puts at 0 to 10°F. No Wisconsin county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Wisconsin winters, not about tea.
Below the zone 7 floor
72 counties
- Bayfield County · zone 4a
- Burnett County · zone 4a
- Douglas County · zone 4a
3 of 72 shown
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.
Zone Comparison
Tea Needs
- USDA Zones: 7-9
- Frost-Free Days: 240+
- Sun: Full Sun
- Mature size: 15 ft tall
- Drought tolerance: Low
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 7-9)
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 Tea 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 tea, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether tea 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.
Timing tuned to sub-state frost dates — Florence 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 tea does not survive a Wisconsin winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Wisconsin under protection.
Frost-free days
Tea wants 240+ frost-free days; a typical Wisconsin site sees ~173 (NOAA Regional Climate Centers ACIS, 1991-2020) — 67 days short of what it needs. A typical Wisconsin 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.
Chill hours
Tea has no winter-chill requirement — its listed minimum is 0 hours (Growable Ground Plant Database). Wisconsin typically banks ~2500 chill hours per winter (from PRISM 1991-2020 climate normals), so chill is not a constraint on this plant here — and not evidence in its favour either. Winter survival and season length are what decide it.
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
Tea likes near-neutral soil (pH 4-6). 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 4.5 and 5.5 — 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.
Your land, not the state average
SSURGO maps about 19.9% of Wisconsin as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Tea has low drought tolerance, so it is the fast-draining end that will cost you — your soil map unit, not the state average, is the real answer.
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. Wisconsin soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Tea 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
Growing tea here specifically
Tea needs sharp drainage and sends deep roots; its growing tissue takes cold to about 32°F (FAO ECOCROP), but in Wisconsin, about 19.9% of soils are poorly-drained (SSURGO), and standing water is what actually kills it.
Build tea up on a coarse, free-draining mound so its crown never sit in saturated soil. How to handle it →
What to actually do about these — and the constraints that apply to every Wisconsin grower, not just tea — is covered on the Wisconsin growing guide.
Timing shifts within Wisconsin
Wisconsin isn't one climate. In Florence County, the last hard freeze (28°F) holds until about May 16 — roughly 21 days later than the recorded state median — so plant tea to your county's window, not the statewide date.
Tea needs about 240 days of frost-free season to complete its cycle. No Wisconsin county gives it that outdoors: even Milwaukee County, the state’s longest season at 217 frost-free days, falls 23 days short — so it needs transplants, a short-season variety, or covered growing.
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, which is 67 days short of what tea needs — so on a typical Wisconsin 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"). Tea's 240-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
Tea draws honeybees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, tea 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 tea, the canonical source is UW–Madison Division of Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Tea in Wisconsin
When can I plant Tea 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 Tea, 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 Tea grown in across Wisconsin?
Wisconsin spans USDA hardiness zones 3b-6a (USDA ARS PHZM 2023). Tea carries a range of zones 7-9, 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). Tea needs 240+ 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 Florence, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for Tea in Wisconsin?
Tea prefers pH 4-6 and well (dry spells) drainage (FAO ECOCROP). 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 Tea actually grow on my specific land in Wisconsin?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores tea 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 tea against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Wisconsin tea 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 tea average
Explore More
Growing guides for tea
Explore Wisconsin county by county
Wisconsin carries 72 counties with their own USDA zone — a sample of the growing pages for tea there:
Where else tea grows
Tea's zone band crosses state lines — these are the states closest to Wisconsin 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 Wisconsin
Wisconsin has a growing page for 806 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
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