Unlikely — Zone Mismatch
Pacific madrone (zones 9-13) does not overlap with Idaho's zone range (3b-8a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
Pacific Madrone is hardy to zone 9, and the warmest ground in Idaho is zone 7 — 2 zones short. Planted in open ground it will not survive a Idaho winter. To grow it here, grow pacific madrone under glass — a greenhouse is the only lift this wide the engine models.
A greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 9-13 (plant) against 4-7 (Idaho). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
Idaho spans zones 3b-8a, 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 pacific madrone against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Pacific Madrone Needs
- USDA Zones: 9-13
- Sun: Part Sun
- Mature size: 50 ft tall
- 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
Plant Zone Range (zones 9-13)
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 Pacific Madrone 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.
Winter standing
Idaho runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for pacific madrone, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether pacific madrone is a permanent planting or a replant-every-spring crop for you turns on your own zone within Idaho; check its hardiness range against that before treating it as long-lived ground.
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
The zone check says pacific madrone does not survive a Idaho winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Idaho under protection.
Chill hours
Pacific Madrone requires ~200 chill hours (32-45°F dormancy window). Idaho typically banks ~2500 chill hours per winter (from PRISM 1991-2020 climate normals), which keeps this plant on track.
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
Pacific Madrone likes near-neutral soil (pH 4.5-7.4). That's the common-ground band across Idaho's volcanic ash and silt loam — a soil test confirms it for your site.
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 pacific madrone is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how pacific madrone 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.
Pacific Madrone in Idaho — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 9-13 (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)
What Else to Consider for Pacific Madrone 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 pacific madrone here specifically
Pacific Madrone wants pH 4.5–7.4 and rates to USDA zones 9–13, but Idaho's soils are dominantly silt loam — the fit is decided by your parcel's own map unit, not the state average.
Match pacific madrone to your parcel's SSURGO map unit — test pH and texture, and amend toward its 4.5–7.4 range. How to handle it →
What to actually do about these — and the constraints that apply to every Idaho grower, not just pacific madrone — 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 pacific madrone to your county's window, not the statewide date.
County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Where in Idaho Pacific Madrone Is Zone-Hardy
Pacific Madrone is rated for USDA zones 9–13. No Idaho county reaches it. Even Payette County, the state’s mildest winter at zone 7a, sits below the plant’s zone 9 floor — so in open ground this one needs winter protection here, or a container that comes under cover.
Across those 44 counties Idaho’s winter-low ladder runs from zone 5a in Bear Lake County to zone 7a in Payette County — 2 USDA zones of spread, which is 20°F between the two counties’ average coldest night of the year. None of that range reaches the band pacific madrone needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Pacific Madrone’s zone 9–13 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Pacific Madrone draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, pacific madrone 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.
Idaho Cooperative Extension
For Idaho-specific cultivar recommendations, planting calendars, and pest pressure for pacific madrone, the canonical source is University of Idaho Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Pacific Madrone native to Idaho?
Pacific Madrone is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Idaho. It can still earn a place in a Idaho garden — the zone comparison above tells you whether it will thrive.
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 Pacific Madrone in Idaho
When can I plant Pacific Madrone 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). No sourced winter-hardiness floor is on record for Pacific Madrone, so this page does not state whether it overwinters in Idaho and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Pacific Madrone grown in across Idaho?
Idaho spans USDA hardiness zones 3b-8a (USDA ARS PHZM 2023). Pacific Madrone carries a range of zones 9-13, 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). Pacific Madrone 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 Valley, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Pacific Madrone native to Idaho?
Pacific Madrone is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Idaho. It can still earn a place in a Idaho garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Pacific Madrone in Idaho?
Pacific Madrone prefers pH 4.5-7.4 (USDA PLANTS). 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 Pacific Madrone actually grow on my specific land in Idaho?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores pacific madrone 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 pacific madrone against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Idaho pacific madrone 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 pacific madrone average
Explore More
Growing guides for pacific madrone
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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