Generally — Most Areas
crape myrtle (zones 6-9) suits most of Washington (4a-9b) — zones 6-9 are in range, and the rest of the state is the exception.
Crape Myrtle in Washington — the short answer
Crape Myrtle in Washington: hardy in zones 6–9, full sun.
- Plant zones
- 6-9
- Rated hardy to zone 6a by NC State Extension Gardener Plant Toolbox, checked Oct 2026. Ceiling: not verified.
- Washington zones
- 4a-9b
- USDA PHZM 2023
- Frost window
- Mar 16 - Apr 15 – Oct 24 - Nov 18
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 131 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
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 crape myrtle 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.
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Washington is not one climate
Washington’s winter-low ladder runs across 39 counties, from zone 6 in Ferry County to zone 9 in San Juan County. That is 30°F between the two counties’ average coldest night — the difference between crape myrtle overwintering in the ground and coming under cover.
The middle half of 39 counties runs 7–8.5 zones, with a median of 7 zones — a 3-zone span end to end.
Measured across 39 Washington counties. USDA PHZM 2023, per county. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
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 crape myrtle (USDA PHZM 2023):
Zone Comparison
Crape Myrtle Needs
- USDA Zones: 6-9
- Sun: Full Sun
- Mature size: 25 ft tall
- Drought tolerance: Medium
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 6-9)
Preferred Soil pH
We haven't confirmed this against a published source yet.
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Crape Myrtle 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 crape myrtle, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether crape myrtle 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.
Timing tuned to sub-state frost dates — Whatcom County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. 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 crape myrtle survives winter in part of Washington, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Chill hours
Crape Myrtle requires ~400 chill hours (32-45°F dormancy window). Washington 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
Crape Myrtle tolerates a wide pH range (pH 4.5-7.5) — 3 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 6.5 — 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, a raised bed lifts the roots above wet ground, or work in compost. pH range, preferred pH and drainage need: We haven't confirmed this against a published source yet.
Your land, not the state average
Washington's soils run mostly silt loam, but SSURGO maps the series, texture, and drainage under your exact parcel. Crape Myrtle needs about 59 inches of workable depth, so it is that horizon — not the surface — you are testing for. That map unit, not the state average, decides how crape myrtle performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Washington soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Crape Myrtle 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
Growing crape myrtle here specifically
Crape Myrtle needs pH 4.5–7.5; Washington's dominant silt loam soils may or may not deliver that, so your parcel's SSURGO map unit is the real test.
Start with a soil test on your own ground and adjust pH and texture to fit crape myrtle's 4.5–7.5 range. How to handle it →
What to actually do about these — and the constraints that apply to every Washington grower, not just crape myrtle — is covered on the Washington growing guide.
Timing shifts within Washington
Washington isn't one climate. In Whatcom County, the last hard freeze (28°F) holds until about May 29 — roughly 54 days later than the recorded state median — so plant crape myrtle 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 Washington Crape Myrtle Is Zone-Hardy
Crape Myrtle is rated for USDA zones 6–9. Every one of Washington’s 39 counties sits inside that band — from Ferry County at zone 6a to San Juan County at zone 9a — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.
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 crape myrtle 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". Crape Myrtle’s zone 6–9 band: Rated hardy to zone 6a by NC State Extension Gardener Plant Toolbox, checked Oct 2026. Ceiling: not verified.. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Crape Myrtle draws honeybees, native bees, and butterflies (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, crape myrtle 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. Pollinator value: We haven't confirmed this against a published source yet.
Good to Know Before You Plant Crape Myrtle
Listed as non-toxic to dogs and cats by a source we can't cite. We haven't confirmed this against a published source yet.
Washington Cooperative Extension
For Washington-specific cultivar recommendations, planting calendars, and pest pressure for crape myrtle, the canonical source is WSU Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Crape Myrtle native to Washington?
No — the USDA PLANTS Database lists Crape Myrtle 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 plants that USDA PLANTS records growing in Washington and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.
State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.
Common Questions About Growing Crape Myrtle in Washington
When can I plant Crape Myrtle 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 Crape Myrtle, 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 Crape Myrtle grown in across Washington?
Washington spans USDA hardiness zones 4a-9b (USDA ARS PHZM 2023). Crape Myrtle carries a range of zones 6-9, 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). Crape Myrtle needs 210+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Whatcom, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Crape Myrtle native to Washington?
No — the USDA PLANTS Database lists Crape Myrtle 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 Crape Myrtle in Washington?
Crape Myrtle tolerates pH 4.5-7.5 and well (dry spells) drainage. We haven't confirmed this against a published source yet. That is a 3-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 Crape Myrtle actually grow on my specific land in Washington?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores crape myrtle against your address's mapped 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 crape myrtle against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Washington crape myrtle averages can't show:
We read public map data around Washington — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Washington crape myrtle average
Explore More
Growing guides for crape myrtle
Explore Washington county by county
Washington carries 39 counties with their own USDA zone — a sample of the growing pages for crape myrtle there:
Where else crape myrtle grows
Crape Myrtle's zone band crosses state lines — these are the states closest to Washington in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Washington
Washington has a growing page for 1,033 plants — a rotating sample of the rest of the shelf.
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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