Generally — Most Areas
brittlebush (zones 10-13) suits most of Hawaii (8b-13a) — zones 10-13 are in range, and the rest of the state is the exception.
Brittlebush in Hawaii — the short answer
Brittlebush in Hawaii: hardy in zones 10–13, full sun, against a state median of ~365 frost-free days.
- Plant zones
- 10-13
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Hawaii zones
- 8b-13a
- USDA PHZM 2023
- Killing freeze
- None on record
- NOAA RCC ACIS 1991-2020
- Shortest county season
- 365 days
- NOAA Regional Climate Centers ACIS station record, 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.
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 brittlebush against your parcel's actual hardiness, soil, and sun.
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Where in Hawaii Fits Best
Even within Hawaii's zones 8b-13a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for brittlebush (USDA PHZM 2023):
Zone Comparison
Brittlebush Needs
- USDA Zones: 10-13
- Frost-Free Days: 365+
- Sun: Full Sun
- Mature size: 4 ft tall
- Drought tolerance: High
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 10-13)
Preferred Soil pH
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 Brittlebush 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, brittlebush 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 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 brittlebush survives winter in part of Hawaii, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Brittlebush wants 365+ frost-free days; a typical Hawaii site sees ~365 (NOAA Regional Climate Centers ACIS station record, 1991-2020). That leaves a tight window — use transplants and pick early-maturing cultivars.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS station record, 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
Brittlebush likes near-neutral soil (pH 7-8.5). That's the common-ground band across Hawaii's volcanic and laterite — a soil test confirms it for your site.
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. Hawaii soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Brittlebush 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 brittlebush — is covered on the Hawaii growing guide.
Timing shifts within Hawaii
Brittlebush needs about 365 days of frost-free season to complete its cycle. Even Hawaii County — Hawaii’s shortest season at 365 frost-free days — clears that by 0 days, so season length isn’t the constraint anywhere in Hawaii. What varies is your own parcel.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Brittlebush's 365-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Brittlebush draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Brittlebush's flowers are not fenced in by a freeze date here: the 1991-2020 record resolves no 28°F killing frost anywhere in Hawaii, so what limits bloom is the plant's own cycle rather than the calendar.
Hawaii Cooperative Extension
For Hawaii-specific cultivar recommendations, planting calendars, and pest pressure for brittlebush, the canonical source is UH Mānoa CTAHR Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Brittlebush native to Hawaii?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Brittlebush as native to Hawaii. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Brittlebush in Hawaii
When can I plant Brittlebush 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 Brittlebush grown in across Hawaii?
Hawaii spans USDA hardiness zones 8b-13a (USDA ARS PHZM 2023). Brittlebush carries a range of zones 10-13, 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). Brittlebush needs 365+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Brittlebush native to Hawaii?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Brittlebush as native to Hawaii. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Brittlebush in Hawaii?
Brittlebush prefers pH 7-8.5 (USDA PLANTS). 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 Brittlebush actually grow on my specific land in Hawaii?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores brittlebush 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 brittlebush against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Hawaii brittlebush averages can't show:
We read public map data around Hawaii — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hawaii brittlebush average
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Growing guides for brittlebush
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