Yes — Strong Match
dusty miller is grown as an annual, so season length decides it here, not a winter zone — and Idaho's typical season runs ~160 frost-free days against the ~70 dusty miller needs.
Sow by about Jul 21
Dusty Miller is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 70 frost-free days and a typical Idaho season runs ~160 frost-free days, leaving 90 days of slack. That is room to sow as late as about Jul 21 and still finish before the usual first freeze (Oct 9).
Want more weeks at either end of that window? How to buy the weeks →
70 frost-free days required against Idaho’s ~160-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Your yard isn't the whole zone.
Dusty Miller is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Idaho site runs ~160 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 dusty miller 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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Zone Comparison
Dusty Miller Needs
- USDA Zones: Data pending
- Frost-Free Days: 70+
- Sun: Full Sun
- Mature size: 2 ft tall
- Picking window: ~150 days of harvest
- Drought tolerance: High
Idaho Has
- USDA Zones: 3b-8a
- Last Hard Freeze (28°F): Apr 26 - May 17
- First Hard Freeze (28°F): Oct 1 - Oct 17
- Annual Rainfall: 8-35 inches
- Common Soils: Volcanic ash, Silt loam, Sandy loam
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 Dusty Miller in Idaho
The frost window
Across Idaho, the last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 137-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.
When to start the seed
Those dates are when dusty miller goes out, not when it starts. It is sown under cover about 10 weeks ahead, so counting back from Idaho's late-side last freeze of May 17 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 (USDA PLANTS Database), counting from the last hard freeze it ripens with 57 days to spare even in Idaho's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Valley 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
Frost-free days
Dusty Miller wants 70+ frost-free days; a typical Idaho site sees ~160 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Dusty Miller needs ~800 GDD (base 50°F) to ripen. The state median runs ~1187 GDD (from PRISM 1991-2020 climate normals), so Idaho'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
Dusty Miller likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Idaho's volcanic ash and silt loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7 — worth knowing before you decide whether a Idaho soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Idaho site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Idaho's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for dusty miller is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how dusty miller performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Idaho soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Dusty Miller in Idaho — Quick Answer
- Verdict: Yes — Strong Match
- Plant Zones: Data pending (USDA PLANTS Database)
- State Zones: 3b-8a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 26 - May 17 to Oct 1 - Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020)
- Days to Maturity: 80 days
What Else to Consider for Dusty Miller in Idaho
Zone compatibility tells you about winter cold survival — but Idaho growers also need to think about:
Short growing season at higher elevations
Arid conditions require irrigation in most of the state
Cold winter snaps can reach -30F in mountain valleys
Growing dusty miller here specifically
Dusty Miller needs pH 5.5–7.5; Idaho's dominant silt loam soils may or may not deliver that, so your parcel's SSURGO map unit is the real test.
Start with a soil test on your own ground and adjust pH and texture to fit dusty miller's 5.5–7.5 range. How to handle it →
What to actually do about these — and the constraints that apply to every Idaho grower, not just dusty miller — is covered on the Idaho growing guide.
Timing shifts within Idaho
Idaho isn't one climate. In Valley County, the last hard freeze (28°F) holds until about Jun 14 — roughly 42 days later than the recorded state median — so plant dusty miller to your county's window, not the statewide date.
Dusty Miller needs about 70 days of frost-free season to complete its cycle. Even Valley County — Idaho’s shortest season at 94 frost-free days — clears that by 24 days, so season length isn’t the constraint anywhere in Idaho. What varies is your own parcel.
Across Idaho’s 44 counties the frost-free season runs from 94 days in Valley County to 216 days in Nez Perce County — a spread of 122 days, which is why a single statewide planting date misleads. The median Idaho county sees 160 frost-free days, leaving dusty miller about 90 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"). Dusty Miller's 70-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
Dusty Miller draws honeybees (low value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, dusty miller can only work that bloom inside Idaho's frost window — roughly 160 days, opening after the last 28°F freeze (Apr 26 - May 17) and closing at the first (Oct 1 - Oct 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Dusty Miller
Dusty Miller is listed as toxic to dogs, cats (all) at a mild level (Cornell). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear. Worth knowing for placement: in Idaho this is a one-season plant and the first hard freeze (Oct 1 - Oct 17) takes it down, so the exposure above is a summer-long one rather than something standing in the bed all year.
Recommended Dusty Miller Varieties for Idaho
Idaho publishes no state variety trial for dusty miller, so we won't invent a "best for Idaho" list. Choose types rated to your USDA hardiness zone (3b-8a), and confirm winter survival and drainage against your own parcel.
Idaho Cooperative Extension
For Idaho-specific cultivar recommendations, planting calendars, and pest pressure for dusty miller, the canonical source is University of Idaho Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Dusty Miller native to Idaho?
No — the USDA PLANTS Database lists Dusty Miller as introduced rather than native in the Lower 48, so it is not part of Idaho's native flora. It grows here as a garden plant; pairing it with a few Idaho natives keeps local pollinators fed too.
Looking for plants that belong here? The Idaho 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 Dusty Miller in Idaho
When can I plant Dusty Miller in Idaho?
Idaho's last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Dusty Miller mature before first frost in Idaho?
Yes — Dusty Miller matures in 80 days (USDA PLANTS Database), and Idaho's dependable hard-freeze-free window runs 137 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 57 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 Dusty Miller grown in across Idaho?
Idaho spans USDA hardiness zones 3b-8a (USDA ARS PHZM 2023). Dusty Miller 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 Idaho site have?
A typical Idaho site sees ~160 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Dusty Miller needs 70+ 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 Valley, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Dusty Miller native to Idaho?
No — the USDA PLANTS Database lists Dusty Miller as introduced rather than native in the Lower 48, so it is not part of Idaho's native flora. It grows here as a garden plant; pairing it with a few Idaho natives keeps local pollinators fed too.
How should I amend the soil for Dusty Miller in Idaho?
Dusty Miller prefers pH 5.5-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across Idaho soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Dusty Miller actually grow on my specific land in Idaho?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores dusty miller 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 Idaho
State-level data is a sketch. Your Growable Ground report scores dusty miller against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Idaho dusty miller averages can't show:
We read public map data around Idaho — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Idaho dusty miller average
Explore More
Growing guides for dusty miller
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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