Can I Grow Good King Henry in Hawaii?

USDA Zones 8b-13a · Plant zone range Data pending

Yes — Strong Match

good king henry 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 ~60 good king henry needs.

No season deadline here

The 1991-2020 record carries no killing freeze for Hawaii, so the season never closes on good king henry — the roughly 60 days it needs can start in any month. What sets your timing here is heat and rainfall, not frost.

Want more weeks at either end of that window? How to buy the weeks →

60 days to maturity against Hawaii’s ~365-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.

Score your parcel · free

Your yard isn't the whole zone.

Good King Henry 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 good king henry against your land's actual frost dates, sun, and soil.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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Zone Comparison

Good King Henry Needs

  • USDA Zones: Data pending
  • Sun: Full Sun
  • Mature size: 1 ft tall
  • Picking window: ~90 days of harvest
  • Drought tolerance: Medium

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

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.58.0

Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Good King Henry 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 60 days to maturity (USDA PLANTS Database) and no frost to close the season, good king henry fits about 6 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: USDA PLANTS Database. 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

Good King Henry matures in ~60 days (Growable Ground Plant Database). 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

Good King Henry likes near-neutral soil (pH 5.5-8). That's the common-ground band across Hawaii's volcanic and laterite — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6 and 7.5 — worth knowing before you decide whether a Hawaii soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Hawaii site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Your land, not the state average

Hawaii's soils run mostly silty clay loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for good king henry is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how good king henry performs.

Check your parcel → Source: USDA NRCS SSURGO.

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.

Good King Henry in Hawaii — Quick Answer

  • Verdict: Yes — Strong Match
  • Plant Zones: Data pending (USDA PLANTS Database)
  • State Zones: 8b-13a (USDA ARS PHZM 2023)
  • Growing Season: year-round — no 28°F killing freeze in Hawaii’s 30-year station record (NOAA Regional Climate Centers ACIS, 1991-2020)
  • Days to Maturity: 60 days

What Else to Consider for Good King Henry 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

Growing good king henry here specifically

Hawaii's soils run mostly silty clay loam (Andisols), and whether that suits good king henry's pH 5.5–8.0 preference comes down to your exact parcel, not the statewide picture.

Pull your parcel's SSURGO map unit, test pH, and amend toward good king henry's 5.5–8.0 target before planting. How to handle it →

What to actually do about these — and the constraints that apply to every Hawaii grower, not just good king henry — is covered on the Hawaii growing guide.

Timing shifts within Hawaii

Good King Henry needs about 60 days of frost-free season from planting to harvest. Even Hawaii County — Hawaii’s shortest season at 365 frost-free days — clears that by 305 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"). Good King Henry's 60-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.

Good to Know Before You Plant Good King Henry

Good King Henry is listed as toxic to dogs, cats (leaves) at a mild level (Cornell). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.

Recommended Good King Henry Varieties for Hawaii

Hawaii publishes no state variety trial for good king henry, so we won't invent a "best for Hawaii" list. Choose types rated to your USDA hardiness zone (8b-13a), and confirm winter survival and drainage against your own parcel.

Hawaii Cooperative Extension

For Hawaii-specific cultivar recommendations, planting calendars, and pest pressure for good king henry, the canonical source is UH Mānoa CTAHR Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Good King Henry native to Hawaii?

No — the USDA PLANTS Database lists Good King Henry as introduced rather than native in the Lower 48, so it is not part of Hawaii's native flora. It grows here as a garden plant; pairing it with a few Hawaii natives keeps local pollinators fed too.

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 Good King Henry in Hawaii

When can I plant Good King Henry 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 Good King Henry grown in across Hawaii?

Hawaii spans USDA hardiness zones 8b-13a (USDA ARS PHZM 2023). Good King Henry carries a range of zones Data pending, 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). Good King Henry 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 Good King Henry native to Hawaii?

No — the USDA PLANTS Database lists Good King Henry as introduced rather than native in the Lower 48, so it is not part of Hawaii's native flora. It grows here as a garden plant; pairing it with a few Hawaii natives keeps local pollinators fed too.

How should I amend the soil for Good King Henry in Hawaii?

Good King Henry prefers pH 5.5-8 and well (dry spells) drainage (Growable Ground Plant 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 Good King Henry actually grow on my specific land in Hawaii?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores good king henry against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in Hawaii

State-level data is a sketch. Your Growable Ground report scores good king henry against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Hawaii good king henry averages can't show:

Your soil pHYour frost-free days — Hawaii averages 365Your sun & shade

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 good king henry average

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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