Yes — Strong Match
snapdragon is grown as an annual, so season length decides it here, not a winter zone — and Colorado's typical season runs ~155 frost-free days against the ~80 snapdragon needs.
Sow by about Jul 20
Snapdragon is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 80 days from sowing to finish and a typical Colorado season runs ~155 frost-free days, leaving 75 days of slack. That is room to sow as late as about Jul 20 and still finish before the usual first freeze (Oct 8).
Want more weeks at either end of that window? How to buy the weeks →
80 days to maturity against Colorado’s ~155-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Snapdragon in Colorado — the short answer
Snapdragon in Colorado: full sun, against a state median of ~155 frost-free days.
- 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
- Days to maturity
- 80 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.
Snapdragon is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Colorado site runs ~155 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 snapdragon against your land's actual frost dates, sun, and soil.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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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 snapdragon 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.
Zone Comparison
Snapdragon Needs
- USDA Zones: Data pending
- Sun: Full Sun
- Mature size: 2.5 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: Low
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
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 Snapdragon 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
Snapdragon takes cold down to about 25°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 snapdragon 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.
Days to maturity vs. the window
At 80 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 53 days to spare even in Colorado's tightest freeze scenario — room for a later start or a second sowing.
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
Days to maturity
Snapdragon matures in ~80 days (Growable Ground Plant Database). A typical Colorado site has ~155 frost-free days, so plenty of room for a second succession.
Growing degree days
Snapdragon needs ~1100 GDD (base 50°F) to ripen. The state median runs ~2083 GDD (from PRISM 1991-2020 climate normals), so Colorado'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
Snapdragon likes near-neutral soil (pH 6.2-7). 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. What matters for snapdragon is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how snapdragon 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 Snapdragon 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 snapdragon here specifically
Colorado's soils run mostly loam (Mollisols), and whether that suits snapdragon's pH 6.2–7.0 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward snapdragon's 6.2–7.0 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Colorado grower, not just snapdragon — 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 snapdragon to your county's window, not the statewide date.
Snapdragon needs about 80 days of frost-free season from planting to harvest. Even Chaffee County — Colorado’s shortest season at 85 frost-free days — clears that by 5 days, so season length isn’t the constraint anywhere in Colorado. What varies is your own parcel.
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 snapdragon about 75 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"). Snapdragon's 80-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Snapdragon draws native bees and hummingbirds (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, snapdragon 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.
Recommended Snapdragon Varieties for Colorado
Colorado publishes no state variety trial for snapdragon, 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 snapdragon, the canonical source is Colorado State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Snapdragon native to Colorado?
No — the USDA PLANTS Database lists Snapdragon as introduced rather than native in the Lower 48, so it is not part of Colorado's native flora. It grows here as a garden plant; pairing it with a few Colorado natives keeps local pollinators fed too.
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 Snapdragon in Colorado
When can I plant Snapdragon 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). Snapdragon takes cold to about 25°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 Snapdragon mature before first frost in Colorado?
Yes — Snapdragon matures in 80 days (Growable Ground Plant Database), and Colorado's dependable hard-freeze-free window runs 133 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 53 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 Snapdragon grown in across Colorado?
Colorado spans USDA hardiness zones 3b-7b (USDA ARS PHZM 2023). Snapdragon carries a range of zones Data pending, 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). Snapdragon should be matched against that window, 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 Snapdragon native to Colorado?
No — the USDA PLANTS Database lists Snapdragon as introduced rather than native in the Lower 48, so it is not part of Colorado's native flora. It grows here as a garden plant; pairing it with a few Colorado natives keeps local pollinators fed too.
How should I amend the soil for Snapdragon in Colorado?
Snapdragon prefers pH 6.2-7 and well (dry spells) drainage (Growable Ground Plant 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 Snapdragon actually grow on my specific land in Colorado?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores snapdragon 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 snapdragon against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Colorado snapdragon 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 snapdragon average
Explore More
Growing guides for snapdragon
Explore Colorado county by county
Colorado carries 64 counties with their own USDA zone — a sample of the growing pages for snapdragon there:
Where else snapdragon grows
Snapdragon's zone band crosses state lines — these are the states closest to Colorado 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 Colorado
Colorado has a growing page for 893 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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