Conditional — Some Areas
willow oak (zones 5-9) reaches only part of Hawaii (8b-13a): zones 8-9 are in range, so where you are in the state decides it.
Your yard isn't the whole zone.
Hawaii spans zones 8b-13a, 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 willow oak against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Willow Oak Needs
- USDA Zones: 5-9
- Sun: Part Sun
- Mature size: 60 ft tall
- Drought tolerance: Medium
Hawaii Has
- USDA Zones: 8b-13a
- Hard Freeze (28°F): None on record — year-round season
- Annual Rainfall: 10-400 inches
- Common Soils: Volcanic, Laterite, Coral sand
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 Willow Oak in Hawaii
The frost window
Hawaii has none — the 1991-2020 station record carries no 28°F killing freeze, so there is no last-frost date to plant after and no first-frost date to harvest before (NOAA Regional Climate Centers ACIS station record). The growing season is year-round; what paces planting here is rainfall, heat and elevation, not the calendar.
Establishment timing
As a long-lived plant, willow oak can go in any month here. Aim for the start of your wetter season so it establishes on rainfall rather than on irrigation, and give it a year in the ground before judging it.
Frost tenderness
Willow Oak is listed frost-tender below 41°F (USDA PLANTS Database), which simply does not bind at low and mid elevation here. It does bind upslope: Hawaii's summit country genuinely freezes, and no station up there carries a long enough daily record for us to date it.
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
Willow Oak likes near-neutral soil (pH 5-7). That's the common-ground band across Hawaii's volcanic and laterite — 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 Hawaii soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Hawaii 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. Hawaii soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Willow Oak in Hawaii — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 5-9 (USDA PLANTS Database)
- State Zones: 8b-13a (USDA ARS PHZM 2023)
- Growing Season: year-round — no 28°F killing freeze in Hawaii’s 30-year station record (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Willow Oak in Hawaii
Zone compatibility tells you about winter cold survival — but Hawaii growers also need to think about:
Extreme rainfall variation — desert on one side, rainforest on the other
Volcanic soil is nutrient-poor in young flows
Invasive species pressure is severe
What to actually do about these — and the constraints that apply to every Hawaii grower, not just willow oak — is covered on the Hawaii growing guide.
Where in Hawaii Willow Oak Is Zone-Hardy
Willow Oak is rated for USDA zones 5–9. Every Hawaii county sits above it. Even Hawaii County, the state’s coldest at zone 10a-11b, is milder than the plant’s zone 9 ceiling — the constraint here is winter chill it will not get, not cold it cannot take.
Across those 5 counties Hawaii’s winter-low ladder runs from zone 10a-11b in Hawaii County to zone 10a-11b in Maui County — 1.5 USDA zones of spread, which is 15°F between the two counties’ average coldest night of the year. None of that range reaches the band willow oak needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Willow Oak’s zone 5–9 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Hawaii Cooperative Extension
For Hawaii-specific cultivar recommendations, planting calendars, and pest pressure for willow oak, the canonical source is UH Mānoa CTAHR Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Willow Oak native to Hawaii?
Willow Oak is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Hawaii. It can still earn a place in a Hawaii garden — the zone comparison above tells you whether it will thrive.
Looking for plants that belong here? The Hawaii 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 Willow Oak in Hawaii
When can I plant Willow Oak in Hawaii?
Any month — Hawaii records no 28°F killing freeze in the 1991-2020 station record, so there is no last-frost date to wait for and the growing season is year-round (NOAA Regional Climate Centers ACIS station record). Pace planting by rainfall, heat and elevation instead: the summit country does freeze, and no station up there carries a long enough record to date it.
What hardiness zone is Willow Oak grown in across Hawaii?
Hawaii spans USDA hardiness zones 8b-13a (USDA ARS PHZM 2023). Willow Oak 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 Hawaii site have?
A typical Hawaii site sees ~365 frost-free days per year (derived from NOAA Regional Climate Centers ACIS station record, 1991-2020). Willow Oak 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 Willow Oak native to Hawaii?
Willow Oak is native to parts of the Lower 48, but the USDA PLANTS Database (accessed 2026-07-01) does not document a native range in Hawaii. It can still earn a place in a Hawaii garden — the zone comparison above tells you whether it will thrive.
How should I amend the soil for Willow Oak in Hawaii?
Willow Oak prefers pH 5-7 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Hawaii soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Willow Oak actually grow on my specific land in Hawaii?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores willow oak 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 Hawaii
State-level data is a sketch. Your Growable Ground report scores willow oak against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Hawaii willow oak averages can't show:
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