Unlikely — Zone Mismatch
New Zealand kauri (zones 9-11) does not overlap with Idaho's zone range (3b-8a). Growing outdoors is unlikely without significant protection.
2 zones short — what would close it
New Zealand Kauri is hardy to zone 9, and the warmest ground in Idaho is zone 7 — 2 zones short. Planted in open ground it will not survive a Idaho winter. To grow it here, grow new zealand kauri under glass — a greenhouse is the only lift this wide the engine models.
A greenhouse is the lift this needs. How a greenhouse changes what you can grow →
Zone math from 9-11 (plant) against 4-7 (Idaho). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.
Your yard isn't the whole zone.
Idaho spans zones 3b-8a, 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 new zealand kauri 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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Zone Comparison
New Zealand Kauri Needs
- USDA Zones: 9-11
- Frost-Free Days: 150+
- Sun: Full Sun
- Mature size: 150 ft tall
- Drought tolerance: Low
Idaho Has
- USDA Zones: 3b-8a
- Last Hard Freeze (28°F): Apr 26 - May 17
- First Hard Freeze (28°F): Oct 1 - Oct 17
- Annual Rainfall: 8-35 inches
- Common Soils: Volcanic ash, Silt loam, 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 New Zealand Kauri in Idaho
The frost window
Across Idaho, the last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 137-day window you can count on — up to 174 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
Idaho runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for new zealand kauri, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether new zealand kauri is a permanent planting or a replant-every-spring crop for you turns on your own zone within Idaho; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Valley County, not the statewide average.
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
The zone check says new zealand kauri does not survive a Idaho winter in the ground. The season figures below measure a different question — whether it could finish a season here at all — and they only bear on Idaho under protection.
Frost-free days
New Zealand Kauri wants 150+ frost-free days; a typical Idaho site sees ~160 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a tight window — use transplants and pick early-maturing cultivars.
Chill hours
New Zealand Kauri has no winter-chill requirement — its listed minimum is 0 hours (USDA PLANTS Database). Idaho typically banks ~2500 chill hours per winter (from PRISM 1991-2020 climate normals), so chill is not a constraint on this plant here — and not evidence in its favour either. Winter survival and season length are what decide it.
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
New Zealand Kauri likes near-neutral soil (pH 4.5-6.5). That's the common-ground band across Idaho's volcanic ash and silt loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 4.8 and 5.5 — worth knowing before you decide whether a Idaho soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Idaho site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Idaho soil pH runs about 6.7–7.4, and that sits above new zealand kauri's tolerated 4.5–6.5, so the typical Idaho parcel needs sulfur to bring it down. SSURGO maps it swinging by full points parcel to parcel, so your map unit, not the state number, decides whether new zealand kauri needs lime or sulfur.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Idaho soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
New Zealand Kauri in Idaho — Quick Answer
- Verdict: Unlikely — Zone Mismatch
- Plant Zones: 9-11 (USDA PLANTS Database)
- State Zones: 3b-8a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 26 - May 17 to Oct 1 - Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for New Zealand Kauri in Idaho
Zone compatibility tells you about winter cold survival — but Idaho growers also need to think about:
Short growing season at higher elevations
Arid conditions require irrigation in most of the state
Cold winter snaps can reach -30F in mountain valleys
Growing new zealand kauri here specifically
New Zealand Kauri prefers acidic soil (pH 4.5–6.5), but Idaho's soils trend alkaline (SSURGO dominant pH near 7.1) — above its range, iron and other micronutrients become unavailable.
Test your soil and acidify with elemental sulfur toward new zealand kauri's 4.5–6.5 range before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Idaho grower, not just new zealand kauri — is covered on the Idaho growing guide.
Timing shifts within Idaho
Idaho isn't one climate. In Valley County, the last hard freeze (28°F) holds until about Jun 14 — roughly 42 days later than the recorded state median — so plant new zealand kauri to your county's window, not the statewide date.
New Zealand Kauri needs about 150 days of frost-free season to complete its cycle. 25 of Idaho’s 44 counties give it that outright. The tightest that does is Lewis County at 156 frost-free days — 6 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
Across Idaho’s 44 counties the frost-free season runs from 94 days in Valley County to 216 days in Nez Perce County — a spread of 122 days, which is why a single statewide planting date misleads. The median Idaho county sees 160 frost-free days, leaving new zealand kauri about 10 days of slack on a typical parcel — room for a second sowing where the season runs long.
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"). New Zealand Kauri's 150-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Idaho Cooperative Extension
For Idaho-specific cultivar recommendations, planting calendars, and pest pressure for new zealand kauri, the canonical source is University of Idaho Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing New Zealand Kauri in Idaho
When can I plant New Zealand Kauri in Idaho?
Idaho's last spring hard freeze (28°F) clears between Apr 26 and May 17, and the first fall hard freeze lands between Oct 1 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for New Zealand Kauri, so this page does not state whether it overwinters in Idaho 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 New Zealand Kauri grown in across Idaho?
Idaho spans USDA hardiness zones 3b-8a (USDA ARS PHZM 2023). New Zealand Kauri 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 Idaho site have?
A typical Idaho site sees ~160 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). New Zealand Kauri needs 150+ 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 Valley, the freeze-free season runs shorter than the state average, so verify your own county's window.
How should I amend the soil for New Zealand Kauri in Idaho?
New Zealand Kauri prefers pH 4.5-6.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Idaho soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will New Zealand Kauri actually grow on my specific land in Idaho?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores new zealand kauri 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 Idaho
State-level data is a sketch. Your Growable Ground report scores new zealand kauri against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Idaho new zealand kauri averages can't show:
We read public map data around Idaho — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Idaho new zealand kauri average
Explore More
Growing guides for new zealand kauri
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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