Generally — Most Areas
trout lily (zones 3-8) suits most of Oregon (5a-10a) — zones 5-8 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
Oregon spans zones 5a-10a, 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 trout lily against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Trout Lily Needs
- USDA Zones: 3-8
- Sun: Shade
- Mature size: 6 in tall
- Picking window: ~14 days of harvest
- Drought tolerance: Low
Oregon Has
- USDA Zones: 5a-10a
- Last Hard Freeze (28°F): Feb 25 - Apr 26
- First Hard Freeze (28°F): Oct 19 - Nov 26
- Annual Rainfall: 8-90 inches
- Common Soils: Volcanic, Silt loam (Willamette), Sandy loam
Plant Zone Range (zones 3-8)
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 Trout Lily in Oregon
The frost window
Across Oregon, the last spring hard freeze (28°F) clears between Feb 25 and Apr 26, and the first fall hard freeze lands between Oct 19 and Nov 26 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 176-day window you can count on — up to 274 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
Oregon runs as cold as USDA zone 5, and no sourced winter-hardiness floor is on record for trout lily, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether trout lily is a permanent planting or a replant-every-spring crop for you turns on your own zone within Oregon; check its hardiness range against that before treating it as long-lived ground.
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.
Soil + Drainage Fit
Trout Lily likes near-neutral soil (pH 5-7). That's the common-ground band across Oregon's volcanic and silt loam (willamette) — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.5 and 6.5 — worth knowing before you decide whether a Oregon soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Oregon 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. Oregon soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Trout Lily in Oregon — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 3-8 (USDA PLANTS Database)
- State Zones: 5a-10a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Feb 25 - Apr 26 to Oct 19 - Nov 26 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Trout Lily in Oregon
Zone compatibility tells you about winter cold survival — but Oregon growers also need to think about:
West side: excessive rain and overcast skies reduce sun for warm-season crops
East side: arid conditions (8-15 inches rainfall) require irrigation
Slug pressure is extreme in western Oregon
Mountain areas have very short seasons (60-90 frost-free days)
What to actually do about these — and the constraints that apply to every Oregon grower, not just trout lily — is covered on the Oregon growing guide.
Where in Oregon Trout Lily Is Zone-Hardy
Trout Lily is rated for USDA zones 3–8. 21 of Oregon’s 36 counties fall inside that band. The coldest that does is Klamath County at zone 6a. 15 counties sit above its zone 8 ceiling, where the limit is too little winter chill rather than too much cold. Where you are in Oregon decides this one.
Across those 36 counties Oregon’s winter-low ladder runs from zone 6a in Klamath County to zone 9b in Curry County — 3.5 USDA zones of spread, which is 35°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.
The planting window moves with it. Klamath County holds its last hard freeze (28°F) until about Jun 9, while Lincoln County is clear by Feb 3 — 126 days apart. Set trout lily out on your county’s date, not the state’s.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". Trout Lily’s zone 3–8 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Where in Oregon Fits Best
Even within Oregon's zones 5a-10a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for trout lily (USDA PHZM 2023):
Pollinator + Wildlife Value
Trout Lily draws native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, trout lily can only work that bloom inside Oregon's frost window — roughly 213 days, opening after the last 28°F freeze (Feb 25 - Apr 26) and closing at the first (Oct 19 - Nov 26), per NOAA Regional Climate Centers ACIS, 1991-2020.
Oregon Cooperative Extension
For Oregon-specific cultivar recommendations, planting calendars, and pest pressure for trout lily, the canonical source is OSU Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Trout Lily native to Oregon?
Trout Lily is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Oregon. It can still earn a place in a Oregon garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The Oregon 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 Trout Lily in Oregon
When can I plant Trout Lily in Oregon?
Oregon's last spring hard freeze (28°F) clears between Feb 25 and Apr 26, and the first fall hard freeze lands between Oct 19 and Nov 26 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Trout Lily, so this page does not state whether it overwinters in Oregon 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 Trout Lily grown in across Oregon?
Oregon spans USDA hardiness zones 5a-10a (USDA ARS PHZM 2023). Trout Lily carries a range of zones 3-8, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Oregon site have?
A typical Oregon site sees ~213 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Trout Lily 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.
Is Trout Lily native to Oregon?
Trout Lily is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Oregon. It can still earn a place in a Oregon garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Trout Lily in Oregon?
Trout Lily prefers pH 5-7 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across Oregon soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Trout Lily actually grow on my specific land in Oregon?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores trout lily 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 Oregon
State-level data is a sketch. Your Growable Ground report scores trout lily against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Oregon trout lily averages can't show:
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