Generally — Most Areas
climbing hydrangea (zones 4-8) suits most of New Hampshire (3b-6b) — zones 4-6 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
New Hampshire spans zones 3b-6b, 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 climbing hydrangea against your parcel's actual hardiness, soil, and sun.
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Zone Comparison
Climbing Hydrangea Needs
- USDA Zones: 4-8
- Frost-Free Days: 120+
- Sun: Part Sun
- Mature size: 50 ft tall
- Drought tolerance: Low
New Hampshire Has
- USDA Zones: 3b-6b
- Last Hard Freeze (28°F): Apr 22 - May 4
- First Hard Freeze (28°F): Oct 10 - Oct 21
- Annual Rainfall: 36-50 inches
- Common Soils: Glacial till, Sandy loam, Rocky loam
Plant Zone Range (zones 4-8)
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 Climbing Hydrangea in New Hampshire
The frost window
Across New Hampshire, the last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 159-day window you can count on — up to 182 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
New Hampshire runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for climbing hydrangea, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether climbing hydrangea is a permanent planting or a replant-every-spring crop for you turns on your own zone within New Hampshire; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Coos 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 climbing hydrangea survives winter in part of New Hampshire, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Climbing Hydrangea wants 120+ frost-free days; a typical New Hampshire site sees ~171 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves a workable window — start indoors to bank time.
Growing degree days
Climbing Hydrangea needs ~1200 GDD (base 50°F) to ripen. The state median runs ~1870 GDD (from PRISM 1991-2020 climate normals), so New Hampshire's typical season clears that easily.
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
Climbing Hydrangea likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across New Hampshire's glacial till and sandy loam — a soil test confirms it for your site. 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 New Hampshire soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your New Hampshire site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 8.5% of New Hampshire as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Climbing Hydrangea has low drought tolerance, so it is the fast-draining end that will cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. New Hampshire soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Climbing Hydrangea in New Hampshire — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 4-8 (USDA PLANTS Database)
- State Zones: 3b-6b (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 22 - May 4 to Oct 10 - Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Climbing Hydrangea in New Hampshire
Zone compatibility tells you about winter cold survival — but New Hampshire growers also need to think about:
Very short season in the White Mountains (80-100 frost-free days)
Rocky glacial soils throughout the state
Harsh winters with deep snow cover
Growing climbing hydrangea here specifically
Climbing Hydrangea wilts without steady moisture and rates to zones 4–8; roughly 15.0% of New Hampshire sits on sandy, excessively-drained ground (SSURGO) that sheds water almost as fast as it falls.
Hold moisture for climbing hydrangea with deep mulch and drip lines, especially on the droughtiest parcels. How to handle it →
What to actually do about these — and the constraints that apply to every New Hampshire grower, not just climbing hydrangea — is covered on the New Hampshire growing guide.
Timing shifts within New Hampshire
New Hampshire isn't one climate. In Coos County, the last hard freeze (28°F) holds until about May 13 — roughly 16 days later than the recorded state median — so plant climbing hydrangea to your county's window, not the statewide date.
Climbing Hydrangea needs about 120 days of frost-free season to complete its cycle. Even Coos County — New Hampshire’s shortest season at 145 frost-free days — clears that by 25 days, so season length isn’t the constraint anywhere in New Hampshire. 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"). Climbing Hydrangea's 120-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Where in New Hampshire Fits Best
Even within New Hampshire's zones 3b-6b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for climbing hydrangea (USDA PHZM 2023):
Pollinator + Wildlife Value
Climbing Hydrangea draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, climbing hydrangea can only work that bloom inside New Hampshire's frost window — roughly 171 days, opening after the last 28°F freeze (Apr 22 - May 4) and closing at the first (Oct 10 - Oct 21), per NOAA Regional Climate Centers ACIS, 1991-2020.
Good to Know Before You Plant Climbing Hydrangea
Climbing Hydrangea is listed as toxic to dogs, cats, horses (leaves, buds) at a moderate level (ASPCA). Most listed plants only cause brief upset — a raised bed or a fenced corner usually keeps curious pets clear.
New Hampshire Cooperative Extension
For New Hampshire-specific cultivar recommendations, planting calendars, and pest pressure for climbing hydrangea, the canonical source is UNH Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Climbing Hydrangea native to New Hampshire?
No — the USDA PLANTS Database lists Climbing Hydrangea as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
Looking for plants that belong here? The New Hampshire 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 Climbing Hydrangea in New Hampshire
When can I plant Climbing Hydrangea in New Hampshire?
New Hampshire's last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Climbing Hydrangea, so this page does not state whether it overwinters in New Hampshire 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 Climbing Hydrangea grown in across New Hampshire?
New Hampshire spans USDA hardiness zones 3b-6b (USDA ARS PHZM 2023). Climbing Hydrangea carries a range of zones 4-8, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical New Hampshire site have?
A typical New Hampshire site sees ~171 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Climbing Hydrangea needs 120+ 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 Coos, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Climbing Hydrangea native to New Hampshire?
No — the USDA PLANTS Database lists Climbing Hydrangea as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
How should I amend the soil for Climbing Hydrangea in New Hampshire?
Climbing Hydrangea prefers pH 5.5-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across New Hampshire soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Climbing Hydrangea actually grow on my specific land in New Hampshire?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores climbing hydrangea 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 New Hampshire
State-level data is a sketch. Your Growable Ground report scores climbing hydrangea against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that New Hampshire climbing hydrangea averages can't show:
We read public map data around New Hampshire — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Hampshire climbing hydrangea average
Explore More
Growing guides for climbing hydrangea
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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