Yes — Strong Match
geranium is grown as an annual, so season length decides it here, not a winter zone — and Hawaii's typical season runs ~365 frost-free days against the ~95 geranium needs.
Geranium in Hawaii — the short answer
Geranium in Hawaii: grown in zones 10–11, part sun, against a state median of ~365 frost-free days.
- Plant zones
- Grown as an annual — see the growing season
- Growing season, not a hardiness zone
- 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
- Days to maturity
- 95 days
- Growable Ground Plant Database
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.
Geranium is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Hawaii site runs ~365 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score geranium against your land's actual frost dates, sun, and soil.
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Hawaii is not one climate
Hawaii’s winter-low ladder runs across 5 counties, from zone 9 in Hawaii County to zone 11.5 in Kalawao County. That is 25°F between the two counties’ average coldest night — the difference between geranium overwintering in the ground and coming under cover.
The middle half of 5 counties runs 10–11.5 zones, with a median of 10 zones — a 2.5-zone span end to end.
Measured across 5 Hawaii 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.
Zone Comparison
Geranium Needs
- USDA Zones: 10-11
- Sun: Part SunWe haven't confirmed this against a published source yet.
- Mature size: 1.5 ft tallWe haven't confirmed this against a published source yet.
- Picking window: ~150 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: MediumWe haven't confirmed this against a published source yet.
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 10-11)
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 Geranium 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.
Days to maturity vs. the window
At 95 days to maturity (Growable Ground Plant Database) and no frost to close the season, geranium fits about 3 plantings a year — so the real limit is what you can keep watered and harvested, not how many days are left.
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
Days to maturity
Geranium matures in ~95 days. We haven't confirmed this against a published source yet. A typical Hawaii site has ~365 frost-free days, so plenty of room for a second succession.
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
Drainage matters: this plant wants well (dry spells). If your Hawaii site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost. Drainage need: We haven't confirmed this against a published source yet.
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 Geranium in Hawaii
The zone range tells you where geranium is grown — 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 geranium — is covered on the Hawaii growing guide.
Timing shifts within Hawaii
Geranium needs about 95 days of frost-free season from planting to harvest. Even Hawaii County — Hawaii’s shortest season at 365 frost-free days — clears that by 270 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"). Geranium's 95-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Geranium draws honeybees and butterflies (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Geranium'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. Pollinator value: We haven't confirmed this against a published source yet.
Hawaii Cooperative Extension
For Hawaii-specific cultivar recommendations, planting calendars, and pest pressure for geranium, the canonical source is UH Mānoa CTAHR Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Geranium in Hawaii
When can I plant Geranium 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 Geranium grown in across Hawaii?
Hawaii spans USDA hardiness zones 8b-13a (USDA ARS PHZM 2023). Geranium carries a range of zones 10-11, 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 ~365 frost-free days per year (derived from NOAA Regional Climate Centers ACIS station record, 1991-2020). Geranium 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.
Will Geranium actually grow on my specific land in Hawaii?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores geranium 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 Hawaii
State-level data is a sketch. Your Growable Ground report scores geranium against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Hawaii geranium 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 geranium average
Explore More
Growing guides for geranium
Explore Hawaii county by county
Hawaii carries 5 counties with their own USDA zone — a sample of the growing pages for geranium there:
Where else geranium grows
Geranium's zone band crosses state lines — these are the states closest to Hawaii 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 Hawaii
Hawaii has a growing page for 789 plants — a rotating sample of the rest of the shelf.
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