Generally — Most Areas
chrysanthemum (zones 5-9) suits most of Colorado (3b-7b) — zones 5-7 are in range, and the rest of the state is the exception.
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 chrysanthemum against your land's actual soil, sun, and frost.
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Zone Comparison
Chrysanthemum Needs
- USDA Zones: 5-9
- Frost-Free Days: 180+
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~45 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 5-9)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Chrysanthemum 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 tenderness
Chrysanthemum is frost-tender — its listed minimum temperature is 37.4°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
When to start the seed
Those dates are when chrysanthemum 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.
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
The zone check says chrysanthemum 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
Chrysanthemum wants 180+ frost-free days; a typical Colorado site sees ~155 (NOAA Regional Climate Centers ACIS, 1991-2020) — 25 days short of what it needs. A typical Colorado 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.
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
Chrysanthemum likes near-neutral soil (pH 5.5-7.3). That's the common-ground band across Colorado's sandy 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 6 and 6.5 — 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.
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.
Chrysanthemum in Colorado — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 5-9 (USDA PLANTS Database)
- State Zones: 3b-7b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 25 - May 19 to Sep 29 - Oct 16 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Chrysanthemum 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
What to actually do about these — and the constraints that apply to every Colorado grower, not just chrysanthemum — is covered on the Colorado growing guide.
Timing shifts within Colorado
Chrysanthemum needs about 180 days of frost-free season to complete its cycle. 11 of Colorado’s 64 counties give it that outright. The tightest that does is Denver County at 183 frost-free days — 3 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, which is 25 days short of what chrysanthemum needs — so on a typical Colorado 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"). Chrysanthemum's 180-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
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 chrysanthemum (USDA PHZM 2023):
Pollinator + Wildlife Value
Chrysanthemum draws honeybees and butterflies (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, chrysanthemum 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.
Colorado Cooperative Extension
For Colorado-specific cultivar recommendations, planting calendars, and pest pressure for chrysanthemum, the canonical source is Colorado State University Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Chrysanthemum in Colorado
When can I plant Chrysanthemum 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). Chrysanthemum is frost-tender — its listed minimum temperature is 37.4°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
What hardiness zone is Chrysanthemum grown in across Colorado?
Colorado spans USDA hardiness zones 3b-7b (USDA ARS PHZM 2023). Chrysanthemum carries a range of zones 5-9, 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). Chrysanthemum needs 180+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
How should I amend the soil for Chrysanthemum in Colorado?
Chrysanthemum prefers pH 5.5-7.3 and well (dry spells) drainage (FAO ECOCROP). 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 Chrysanthemum actually grow on my specific land in Colorado?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores chrysanthemum 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 chrysanthemum against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Colorado chrysanthemum averages can't show:
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