Conditional — Some Areas
clethra (zones 5-11) has limited zone overlap with Hawaii (10a-13a). Only zones 10-11 in the state are suitable.
Your yard isn't the whole zone.
Hawaii spans zones 10a-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 clethra against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Zone Comparison
Clethra Needs
- USDA Zones: 5-11
- Soil pH: 4.5 - 7
- Sun: Part Sun
- Frost-Free Days: 150+
Hawaii Has
- USDA Zones: 10a-13a
- Last Frost: None
- First Frost: None
- Annual Rainfall: 10-400 inches
- Common Soils: Volcanic, Laterite, Coral sand
Plant Zone Range (zones 5-11)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
Growing Season Fit
Zone compatibility says you can survive winter here. Whether the growing season is long enough — and warm enough — is a different question.
Frost-free days
Clethra wants 150+ frost-free days; a typical Hawaii site sees ~350 (NOAA Climate Normals). That leaves comfortable headroom for succession planting.
Chill hours
Clethra requires ~500 chill hours (32-45°F dormancy window). Hawaii typically banks ~150 chill hours per winter, short of this plant's requirement — fruit set may suffer in mild years without a low-chill cultivar.
Climate aggregates derive from USDA NRCS county-level hardiness data + Cornell CALS Extension GDD-by-region tables + MSU Extension chill-hours-by-zone (1991-2020 NOAA Climate Normals baseline).
Soil + Drainage Fit
Clethra likes near-neutral soil (pH 4.5-7). That's the common-ground band across Hawaii's volcanic and laterite — a soil test confirms it for your site.
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.
Clethra in Hawaii — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 5-11 (USDA PLANTS Database)
- State Zones: 10a-13a (USDA ARS PHZM 2023)
- Growing Season: None to None (NOAA Climate Normals)
What Else to Consider
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
Your side of the island decides everything — check your exact spot's rainfall before choosing crops.
Volcanic soil is nutrient-poor in young flows
A soil test shows what young lava ground is missing — compost and targeted amendments close the gap fast.
Invasive species pressure is severe
Source clean plant material and learn the current watch list — your extension office is the authority on what to keep out.
Where in Hawaii Fits Best
Even within Hawaii's zones 10a-13a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for clethra (USDA PHZM 2023):
Pollinator + Wildlife Value
Clethra draws pollinators (high value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Hawaii Cooperative Extension
For Hawaii-specific cultivar recommendations, planting calendars, and pest pressure for clethra, the canonical source is UH Mānoa CTAHR Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Clethra native to Hawaii?
Clethra 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 Clethra in Hawaii
When can I plant Clethra in Hawaii?
Hawaii's last spring frost runs none and first fall frost none (NOAA Climate Normals 1991-2020). Time outdoor planting to after the last-frost window for your specific site, and pull from those dates for transplant scheduling.
What hardiness zone is Clethra grown in across Hawaii?
Hawaii spans USDA hardiness zones 10a-13a (USDA ARS PHZM 2023). Clethra carries a range of zones 5-11, 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 ~350 frost-free days per year (derived from NOAA Climate Normals 1991-2020). Clethra needs 150+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Clethra native to Hawaii?
Clethra 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 Clethra in Hawaii?
Clethra prefers pH 4.5-7 (USDA PLANTS Database). 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 Clethra actually grow on my specific land in Hawaii?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores clethra 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 clethra against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds