Generally — Most Areas
lupine (zones 4-7) suits most of Colorado (3b-7b) — zones 4-7 are in range, and the rest of the state is the exception.
Lupine in Colorado — the short answer
Lupine in Colorado: hardy in zones 4–7, full sun, against a state median of ~155 frost-free days.
- Plant zones
- 4-7
- 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
- Colorado zones
- 3b-7b
- USDA PHZM 2023
- Frost window
- Apr 25 - May 19 – Sep 29 - Oct 16
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 85 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.
Colorado spans zones 3b-7b, 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 lupine against your land's actual soil, sun, and frost.
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Colorado is not one climate
A single Colorado answer averages 64 counties whose growing seasons are 124 days apart — from 85 frost-free days in Chaffee County to 209 in Mesa County. Which end of that your land sits nearer changes what lupine can finish before the first hard freeze.
The middle half of 64 counties runs 132–174 days, with a median of 150 days — a 124-day span end to end.
Measured across 64 Colorado 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 Colorado Fits Best
Even within Colorado's zones 3b-7b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for lupine (USDA PHZM 2023):
Zone Comparison
Lupine Needs
- USDA Zones: 4-7
- Frost-Free Days: 100+
- Sun: Full Sun
- Mature size: 4 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Medium
Colorado Has
- USDA Zones: 3b-7b
- Last Hard Freeze (28°F): Apr 25 - May 19
- First Hard Freeze (28°F): Sep 29 - Oct 16
- Annual Rainfall: 7-20 inches
- Common Soils: Sandy loam, Clay loam, Alkaline caliche
Plant Zone Range (zones 4-7)
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 Lupine in Colorado
The frost window
Across Colorado, the last spring hard freeze (28°F) clears between Apr 25 and May 19, and the first fall hard freeze lands between Sep 29 and Oct 16 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 133-day window you can count on — up to 174 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
Lupine takes cold down to about 21.2°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Colorado'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
Those dates are when lupine goes out, not when it starts. It is sown under cover about 8 weeks ahead, so counting back from Colorado's late-side last freeze of May 19 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Timing tuned to sub-state frost dates — Chaffee 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 lupine survives winter in part of Colorado, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Lupine wants 100+ frost-free days; a typical Colorado site sees ~155 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.
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
Lupine tolerates a wide pH range (pH 4.9-8.2) — 3.3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Colorado. 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 7 — worth knowing before you decide whether a Colorado soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Colorado site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Colorado's soils run mostly loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Lupine needs about 59 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how lupine performs.
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. Colorado soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Lupine in Colorado
Zone compatibility tells you about winter cold survival — but Colorado growers also need to think about:
Low annual rainfall (7-20 inches) means irrigation is essential nearly everywhere
High altitude UV and temperature swings stress plants
Very short growing season at elevation (60-90 frost-free days above 8,000 ft)
Alkaline soils (pH 7.5-8.5) limit acid-loving plants without amendment
Growing lupine here specifically
Colorado's soils run mostly loam (Mollisols), and whether that suits lupine's pH 4.9–8.2 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward lupine's 4.9–8.2 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Colorado grower, not just lupine — is covered on the Colorado growing guide.
Timing shifts within Colorado
Colorado isn't one climate. In Chaffee County, the last hard freeze (28°F) holds until about Jun 12 — roughly 38 days later than the recorded state median — so plant lupine to your county's window, not the statewide date.
Lupine needs about 100 days of frost-free season to complete its cycle. 60 of Colorado’s 64 counties give it that outright. The tightest that does is Summit County at 102 frost-free days — 2 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Colorado’s 64 counties the frost-free season runs from 85 days in Chaffee County to 209 days in Mesa County — a spread of 124 days, which is why a single statewide planting date misleads. The median Colorado county sees 155 frost-free days, leaving lupine about 55 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"). Lupine's 100-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
Lupine draws native bees and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, lupine can only work that bloom inside Colorado's frost window — roughly 155 days, opening after the last 28°F freeze (Apr 25 - May 19) and closing at the first (Sep 29 - Oct 16), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Lupine
Lupine 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 Colorado this is a one-season plant and the first hard freeze (Sep 29 - Oct 16) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Lupine Varieties for Colorado
Colorado publishes no state variety trial for lupine, so we won't invent a "best for Colorado" list. Choose types rated to your USDA hardiness zone (3b-7b), and confirm winter survival and drainage against your own parcel.
Colorado Cooperative Extension
For Colorado-specific cultivar recommendations, planting calendars, and pest pressure for lupine, the canonical source is Colorado State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Lupine native to Colorado?
Lupine is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Colorado. It can still earn a place in a Colorado garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The Colorado 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 Lupine in Colorado
When can I plant Lupine in Colorado?
Colorado's last spring hard freeze (28°F) clears between Apr 25 and May 19, and the first fall hard freeze lands between Sep 29 and Oct 16 (NOAA Regional Climate Centers ACIS, 1991-2020). Lupine takes cold to about 21.2°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.
What hardiness zone is Lupine grown in across Colorado?
Colorado spans USDA hardiness zones 3b-7b (USDA ARS PHZM 2023). Lupine carries a range of zones 4-7, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Colorado site have?
A typical Colorado site sees ~155 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Lupine needs 100+ 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 Chaffee, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Lupine native to Colorado?
Lupine is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Colorado. It can still earn a place in a Colorado garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Lupine in Colorado?
Lupine tolerates pH 4.9-8.2 and well (dry spells) drainage (FAO ECOCROP). That is a 3.3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Colorado site — amend for drainage and organic matter first.
Will Lupine actually grow on my specific land in Colorado?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores lupine 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 Colorado
State-level data is a sketch. Your Growable Ground report scores lupine against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Colorado lupine averages can't show:
We read public map data around Colorado — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Colorado lupine average
Explore More
Growing guides for lupine
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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