Generally — Most Areas
butterfly weed (zones 4-10) partially overlaps with Colorado (3a-7a). It can grow in zones 4-7 within the state.
Your yard isn't the whole zone.
Colorado spans zones 3a-7a, 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 butterfly weed 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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Zone Comparison
Butterfly Weed Needs
- USDA Zones: 4-10
- Soil pH: 4.5 - 7.5
- Sun: Full Sun
- Drainage: well (dry spells)
- Frost-Free Days: 120+
Colorado Has
- USDA Zones: 3a-7a
- Last Frost: Apr 15 - Jun 15
- First Frost: Aug 25 - Oct 15
- Annual Rainfall: 7-20 inches
- Common Soils: Sandy loam, Clay loam, Alkaline caliche
Plant Zone Range (zones 4-10)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Butterfly Weed in Colorado
The frost window
Across Colorado, the last spring frost clears between Apr 15 and Jun 15, and the first fall frost lands between Aug 25 and Oct 15 (NOAA Climate Normals 1991-2020). Counting from the latest last frost to the earliest first frost, that's a 71-day window you can count on — up to 183 days on a mild site in a kind year.
Frost tenderness
Butterfly Weed is frost-tender — its listed minimum temperature is 53.6°F (USDA PLANTS Database) — so set plants out after the last frost has cleared your local site, not the state's earliest date.
Establishment timing
As a long-lived plant, butterfly weed isn't racing the calendar to a harvest date. Plant it in spring once the last-frost window passes so roots settle in through the full season, or in early fall while the soil still holds summer warmth.
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
Zone compatibility says you can survive winter here. Whether the growing season is long enough — and warm enough — is a different question.
Frost-free days
Butterfly Weed wants 120+ frost-free days; a typical Colorado site sees ~190 (NOAA Climate Normals). That leaves comfortable headroom for succession planting.
Climate aggregates derive from USDA NRCS county-level hardiness data + Cornell CALS Extension GDD-by-region tables + MSU Extension chill-hours-by-zone (1991-2020 NOAA Climate Normals baseline).
Soil + Drainage Fit
Butterfly Weed likes near-neutral soil (pH 4.5-7.5). That's the common-ground band across Colorado's sandy loam and clay loam — a soil test confirms it for your site. 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 — that map unit, not the state average, decides how butterfly weed performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Colorado soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Butterfly Weed in Colorado — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 4-10 (USDA PLANTS Database)
- State Zones: 3a-7a (USDA ARS PHZM 2023)
- Growing Season: Apr 15 - Jun 15 to Aug 25 - Oct 15 (NOAA Climate Normals)
What Else to Consider
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
Build the irrigation first — drip plus mulch makes a high-desert garden run on remarkably little water.
High altitude UV and temperature swings stress plants
Harden transplants gradually, shade-cloth their first high-sun week, and keep row covers handy for cold nights.
Very short growing season at elevation (60-90 frost-free days above 8,000 ft)
Above 8,000 feet, count your real frost-free days and choose varieties bred to finish inside them.
Alkaline soils (pH 7.5-8.5) limit acid-loving plants without amendment
A soil test tells you your actual pH — grow acid-lovers in containers of amended mix while the native ground grows everything else.
Growing butterfly weed here specifically
Colorado's soils run mostly loam (Mollisols), and whether that suits butterfly weed's pH 4.5–7.5 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward butterfly weed's 4.5–7.5 target before planting. How to handle it →
Timing shifts within Colorado
Colorado isn't one climate. In Lake County, the last hard freeze (28°F) holds until about Jun 2 — roughly 39 days later than the recorded state median — so plant butterfly weed to your county's window, not the statewide date.
County last-freeze dates: NOAA/PRISM Climate Normals 1991-2020, 28°F threshold (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Butterfly Weed draws pollinators (high value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Good to Know Before You Plant Butterfly Weed
Butterfly Weed is listed as toxic to dogs, cats (all) at a moderate level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
Recommended Butterfly Weed Varieties for Colorado
Colorado publishes no state variety trial for butterfly weed, so we won't invent a "best for Colorado" list. Choose types rated to your USDA hardiness zone (3a-7a), and confirm winter survival and drainage against your own parcel.
Colorado Cooperative Extension
For Colorado-specific cultivar recommendations, planting calendars, and pest pressure for butterfly weed, the canonical source is Colorado State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Butterfly Weed native to Colorado?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Butterfly Weed as native to Colorado. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Butterfly Weed in Colorado
When can I plant Butterfly Weed in Colorado?
Colorado's last spring frost clears between Apr 15 and Jun 15, and the first fall frost lands between Aug 25 and Oct 15 (NOAA Climate Normals 1991-2020). Butterfly Weed is a long-lived planting, so target spring just after your local last frost — or early fall while the soil holds warmth — and let it establish through the season.
What hardiness zone is Butterfly Weed grown in across Colorado?
Colorado spans USDA hardiness zones 3a-7a (USDA ARS PHZM 2023). Butterfly Weed carries a range of zones 4-10, 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 ~190 frost-free days per year (derived from NOAA Climate Normals 1991-2020). Butterfly Weed needs 120+ 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 Butterfly Weed native to Colorado?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Butterfly Weed as native to Colorado. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Butterfly Weed in Colorado?
Butterfly Weed prefers pH 4.5-7.5 and well (dry spells) drainage (USDA PLANTS Database). That sits in the common-ground band across Colorado soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Butterfly Weed actually grow on my specific land in Colorado?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores butterfly weed 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 butterfly weed against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
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 →