Yes — Strong Match
white lupin (zones 5-10) covers every zone Illinois contains (5a-7b), so hardiness is not what limits it anywhere in the state.
White Lupin in Illinois — the short answer
White Lupin in Illinois: hardy in zones 5–10, full sun, against a state median of ~212 frost-free days.
- Plant zones
- 5-10
- 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
- Illinois zones
- 5a-7b
- USDA PHZM 2023
- Frost window
- Mar 29 - Apr 8 – Oct 28 - Nov 5
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 177 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 120 days
- Growable Ground Plant Database
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.
White Lupin is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Illinois site runs ~212 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score white lupin against your land's actual frost dates, sun, and soil.
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Illinois is not one climate
A single Illinois answer averages 102 counties whose growing seasons are 67 days apart — from 177 frost-free days in Jo Daviess County to 244 in Alexander County. Which end of that your land sits nearer changes what white lupin can finish before the first hard freeze.
The middle half of 102 counties runs 203–221 days, with a median of 212 days — a 67-day span end to end.
Measured across 102 Illinois counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. 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 Illinois Fits Best
Even within Illinois's zones 5a-7b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for white lupin (USDA PHZM 2023):
Zone Comparison
White Lupin Needs
- USDA Zones: 5-10
- Frost-Free Days: 90+
- Sun: Full Sun
- Mature size: 3 ft tall
- Drought tolerance: Low
Illinois Has
- USDA Zones: 5a-7b
- Last Hard Freeze (28°F): Mar 29 - Apr 8
- First Hard Freeze (28°F): Oct 28 - Nov 5
- Annual Rainfall: 34-48 inches
- Common Soils: Prairie loam, Silt loam, Clay loam
Plant Zone Range (zones 5-10)
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 White Lupin in Illinois
The frost window
Across Illinois, the last spring hard freeze (28°F) clears between Mar 29 and Apr 8, and the first fall hard freeze lands between Oct 28 and Nov 5 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 203-day window you can count on — up to 221 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 hardiness
White Lupin takes cold down to about 26.6°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Illinois's window — even a few weeks before the final hard freeze. 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
White Lupin is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Illinois's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 120 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 83 days to spare even in Illinois's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Jo Daviess 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 white lupin survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
White Lupin wants 90+ frost-free days; a typical Illinois site sees ~212 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
White Lupin needs ~1200 GDD (base 50°F) to ripen. The state median runs ~3352 GDD (from PRISM 1991-2020 climate normals), so Illinois's typical season clears that easily.
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
White Lupin tolerates a wide pH range (pH 4.8-8.2) — 3.4 units, acid ground through alkaline — so soil acidity is rarely what limits it in Illinois. 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 6.4 — worth knowing before you decide whether a Illinois soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Illinois 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 52.0% of Illinois as poorly or somewhat-poorly drained, and the class flips parcel to parcel. White Lupin 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. Illinois soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for White Lupin in Illinois
Zone compatibility tells you about winter cold survival — but Illinois growers also need to think about:
Heavy clay soils in northern IL drain poorly
Extreme temperature swings between summer and winter
Japanese beetles are a major garden pest
Growing white lupin here specifically
White Lupin rates to USDA zones 5–10 and takes frost damage on growing tissue around 26°F (FAO ECOCROP), but cold isn't the risk in Illinois — wet is: with roughly 52.0% of its soils poorly-drained (SSURGO), soggy ground rots the roots.
Give white lupin a raised bed or mounded row with coarse amendment so its roots never sit wet. How to handle it →
What to actually do about these — and the constraints that apply to every Illinois grower, not just white lupin — is covered on the Illinois growing guide.
Timing shifts within Illinois
Illinois isn't one climate. In Jo Daviess County, the last hard freeze (28°F) holds until about Apr 22 — roughly 20 days later than the recorded state median — so plant white lupin to your county's window, not the statewide date.
White Lupin needs about 90 days of frost-free season to complete its cycle. Even Jo Daviess County — Illinois’s shortest season at 177 frost-free days — clears that by 87 days, so season length isn’t the constraint anywhere in Illinois. What varies is your own parcel.
Across Illinois’s 102 counties the frost-free season runs from 177 days in Jo Daviess County to 244 days in Alexander County — a spread of 67 days, which is why a single statewide planting date misleads. The median Illinois county sees 212 frost-free days, leaving white lupin about 122 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"). White Lupin's 90-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
White Lupin draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, white lupin can only work that bloom inside Illinois's frost window — roughly 212 days, opening after the last 28°F freeze (Mar 29 - Apr 8) and closing at the first (Oct 28 - Nov 5), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant White Lupin
White Lupin is listed as toxic to dogs, cats, horses (seeds, pods) at a moderate 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 Illinois this is a one-season plant and the first hard freeze (Oct 28 - Nov 5) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Illinois Cooperative Extension
For Illinois-specific cultivar recommendations, planting calendars, and pest pressure for white lupin, the canonical source is University of Illinois Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is White Lupin native to Illinois?
No — the USDA PLANTS Database lists White Lupin as introduced rather than native in the Lower 48, so it is not part of Illinois's native flora. It grows here as a garden plant; pairing it with a few Illinois natives keeps local pollinators fed too.
Looking for plants that belong here? The Illinois 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 White Lupin in Illinois
When can I plant White Lupin in Illinois?
Illinois's last spring hard freeze (28°F) clears between Mar 29 and Apr 8, and the first fall hard freeze lands between Oct 28 and Nov 5 (NOAA Regional Climate Centers ACIS, 1991-2020). White Lupin takes cold to about 26.6°F before a freeze kills it (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor), so plant on the early side of that window — even ahead of the final hard freeze.
Can White Lupin mature before first frost in Illinois?
Yes — White Lupin matures in 120 days (Growable Ground Plant Database), and Illinois's dependable hard-freeze-free window runs 203 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 83 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is White Lupin grown in across Illinois?
Illinois spans USDA hardiness zones 5a-7b (USDA ARS PHZM 2023). White Lupin carries a range of zones 5-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Illinois site have?
A typical Illinois site sees ~212 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). White Lupin needs 90+ 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 Jo Daviess, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is White Lupin native to Illinois?
No — the USDA PLANTS Database lists White Lupin as introduced rather than native in the Lower 48, so it is not part of Illinois's native flora. It grows here as a garden plant; pairing it with a few Illinois natives keeps local pollinators fed too.
How should I amend the soil for White Lupin in Illinois?
White Lupin tolerates pH 4.8-8.2 and well (dry spells) drainage (FAO ECOCROP). That is a 3.4-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Illinois site — amend for drainage and organic matter first.
Will White Lupin actually grow on my specific land in Illinois?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores white lupin 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 Illinois
State-level data is a sketch. Your Growable Ground report scores white lupin against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Illinois white lupin averages can't show:
We read public map data around Illinois — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Illinois white lupin average
Explore More
Growing guides for white lupin
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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