Conditional — Some Areas
pomelo (zones 9-11) reaches only part of Washington (4a-9b): zone 9 are in range, so where you are in the state decides it.
Your yard isn't the whole zone.
Washington spans zones 4a-9b, 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 pomelo against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Pomelo Needs
- USDA Zones: 9-11
- Sun: Full Sun
Washington Has
- USDA Zones: 4a-9b
- Last Hard Freeze (28°F): Mar 16 - Apr 15
- First Hard Freeze (28°F): Oct 24 - Nov 18
- Annual Rainfall: 6-90 inches
- Common Soils: Volcanic ash, Silt loam (Palouse), Sandy loam
Plant Zone Range (zones 9-11)
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 Pomelo in Washington
The frost window
Across Washington, the last spring hard freeze (28°F) clears between Mar 16 and Apr 15, and the first fall hard freeze lands between Oct 24 and Nov 18 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 192-day window you can count on — up to 247 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
Washington runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for pomelo, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether pomelo is a permanent planting or a replant-every-spring crop for you turns on your own zone within Washington; 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
Pomelo tolerates a wide pH range (pH 4.5-8) — 3.5 units, acid ground through alkaline — so soil acidity is rarely what limits it in Washington. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 7 — worth knowing before you decide whether a Washington soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Washington 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. Washington soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Pomelo in Washington — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 9-11 (USDA PLANTS Database)
- State Zones: 4a-9b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Mar 16 - Apr 15 to Oct 24 - Nov 18 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Pomelo in Washington
Zone compatibility tells you about winter cold survival — but Washington growers also need to think about:
Extreme rain divide: 90+ inches west, 6 inches east of Cascades
East side requires irrigation — no rain from June through September
Slug and root rot pressure on the wet west side
Short seasons at elevation in the Cascades and northeast corners
What to actually do about these — and the constraints that apply to every Washington grower, not just pomelo — is covered on the Washington growing guide.
Where in Washington Pomelo Is Zone-Hardy
Pomelo is rated for USDA zones 9–11. 1 of Washington’s 39 counties fall inside that band. The coldest that does is San Juan County at zone 9a. 38 counties sit below the plant’s zone 9 floor, where an unprotected plant is relying on snow cover and a mild year. Where you are in Washington decides this one.
Across those 39 counties Washington’s winter-low ladder runs from zone 6a in Ferry County to zone 9a in San Juan County — 3 USDA zones of spread, which is 30°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. Whatcom County holds its last hard freeze (28°F) until about May 29, while Island County is clear by Feb 8 — 110 days apart. Set pomelo 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". Pomelo’s zone 9–11 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 Washington Fits Best
Even within Washington's zones 4a-9b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for pomelo (USDA PHZM 2023):
Pollinator + Wildlife Value
Pomelo draws honeybees (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, pomelo can only work that bloom inside Washington's frost window — roughly 208 days, opening after the last 28°F freeze (Mar 16 - Apr 15) and closing at the first (Oct 24 - Nov 18), per NOAA Regional Climate Centers ACIS, 1991-2020.
Washington Cooperative Extension
For Washington-specific cultivar recommendations, planting calendars, and pest pressure for pomelo, the canonical source is WSU Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Pomelo native to Washington?
No — the USDA PLANTS Database lists Pomelo as introduced rather than native in the Lower 48, so it is not part of Washington's native flora. It grows here as a garden plant; pairing it with a few Washington natives keeps local pollinators fed too.
Looking for plants that belong here? The Washington 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 Pomelo in Washington
When can I plant Pomelo in Washington?
Washington's last spring hard freeze (28°F) clears between Mar 16 and Apr 15, and the first fall hard freeze lands between Oct 24 and Nov 18 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Pomelo, so this page does not state whether it overwinters in Washington 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 Pomelo grown in across Washington?
Washington spans USDA hardiness zones 4a-9b (USDA ARS PHZM 2023). Pomelo carries a range of zones 9-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Washington site have?
A typical Washington site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Pomelo 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 Pomelo native to Washington?
No — the USDA PLANTS Database lists Pomelo as introduced rather than native in the Lower 48, so it is not part of Washington's native flora. It grows here as a garden plant; pairing it with a few Washington natives keeps local pollinators fed too.
How should I amend the soil for Pomelo in Washington?
Pomelo tolerates pH 4.5-8 and well (dry spells) drainage (FAO ECOCROP). That is a 3.5-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Washington site — amend for drainage and organic matter first.
Will Pomelo actually grow on my specific land in Washington?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores pomelo 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 Washington
State-level data is a sketch. Your Growable Ground report scores pomelo against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Washington pomelo averages can't show:
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