Conditional — Some Areas
alder (zones 6-12) reaches only part of Vermont (4a-6a): zone 6 are in range, so where you are in the state decides it.
One zone short — what would close it
Alder is hardy to zone 6, and the warmest ground in Vermont is zone 5 — 1 zone short. Planted in open ground it will not survive a Vermont winter. To grow it here, grow alder in a container and move it under cover for the coldest weeks, or give it a greenhouse.
Season extension and overwintering under cover both work at this margin. How to buy the weeks →
Zone math from 6-12 (plant) against 3-5 (Vermont). 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.
Vermont spans zones 4a-6a, 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 alder 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.
No card required · your full report in seconds
Zone Comparison
Alder Needs
- USDA Zones: 6-12
- Sun: Part Sun
- Mature size: 50 ft tall
- Drought tolerance: Medium
Vermont Has
- USDA Zones: 4a-6a
- Last Hard Freeze (28°F): Apr 27 - May 5
- First Hard Freeze (28°F): Oct 10 - Oct 17
- Annual Rainfall: 34-44 inches
- Common Soils: Glacial till, Clay, Silt loam
Plant Zone Range (zones 6-12)
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 Alder in Vermont
The frost window
Across Vermont, the last spring hard freeze (28°F) clears between Apr 27 and May 5, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 158-day window you can count on — up to 173 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
Vermont runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for alder, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether alder is a permanent planting or a replant-every-spring crop for you turns on your own zone within Vermont; check its hardiness range against that before treating it as long-lived ground.
Timing tuned to sub-state frost dates — Essex 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 alder survives winter in part of Vermont, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Chill hours
Alder requires ~500 chill hours (32-45°F dormancy window). Vermont typically banks ~2500 chill hours per winter (from PRISM 1991-2020 climate normals), which keeps this plant on track.
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
Alder likes near-neutral soil (pH 4.4-7.2). That's the common-ground band across Vermont's glacial till and clay — a soil test confirms it for your site. Drainage requirement: poorly (saturated >50% of year). A soil-survey lookup (NRCS SSURGO) flags whether your specific site matches.
Your land, not the state average
Vermont's soils run mostly fine sandy loam, but SSURGO maps the series, texture, and drainage under your exact parcel. What matters for alder is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how alder performs.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH and drainage requirements from USDA PLANTS Database. Vermont soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Alder in Vermont — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 6-12 (USDA PLANTS Database)
- State Zones: 4a-6a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Apr 27 - May 5 to Oct 10 - Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020)
What Else to Consider for Alder in Vermont
Zone compatibility tells you about winter cold survival — but Vermont growers also need to think about:
Short growing season (100-130 frost-free days)
Rocky soils throughout the Green Mountains
Heavy clay in the Champlain Valley
Growing alder here specifically
Vermont's soils run mostly fine sandy loam (Spodosols), and whether that suits alder's pH 4.4–7.2 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward alder's 4.4–7.2 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Vermont grower, not just alder — is covered on the Vermont growing guide.
Timing shifts within Vermont
Vermont isn't one climate. In Essex County, the last hard freeze (28°F) holds until about May 13 — roughly 11 days later than the recorded state median — so plant alder to your county's window, not the statewide date.
County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.
Where in Vermont Alder Is Zone-Hardy
Alder is rated for USDA zones 6–12. No Vermont county reaches it. Even Windsor County, the state’s mildest winter at zone 5b, sits below the plant’s zone 6 floor — so in open ground this one needs winter protection here, or a container that comes under cover.
Across those 14 counties Vermont’s winter-low ladder runs from zone 4b in Caledonia County to zone 5b in Windsor County — 1 USDA zone of spread, which is 10°F between the two counties’ average coldest night of the year. None of that range reaches the band alder needs, so here the statewide answer really is the answer.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Alder’s zone 6–12 band: USDA PLANTS / Growable Ground plant database. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Vermont Cooperative Extension
For Vermont-specific cultivar recommendations, planting calendars, and pest pressure for alder, the canonical source is UVM Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Alder native to Vermont?
No — the USDA PLANTS Database lists Alder as introduced rather than native in the Lower 48, so it is not part of Vermont's native flora. It grows here as a garden plant; pairing it with a few Vermont natives keeps local pollinators fed too.
Looking for plants that belong here? The Vermont 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 Alder in Vermont
When can I plant Alder in Vermont?
Vermont's last spring hard freeze (28°F) clears between Apr 27 and May 5, and the first fall hard freeze lands between Oct 10 and Oct 17 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Alder, so this page does not state whether it overwinters in Vermont 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 Alder grown in across Vermont?
Vermont spans USDA hardiness zones 4a-6a (USDA ARS PHZM 2023). Alder carries a range of zones 6-12, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Vermont site have?
A typical Vermont site sees ~163 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Alder 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. In cooler counties like Essex, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Alder native to Vermont?
No — the USDA PLANTS Database lists Alder as introduced rather than native in the Lower 48, so it is not part of Vermont's native flora. It grows here as a garden plant; pairing it with a few Vermont natives keeps local pollinators fed too.
How should I amend the soil for Alder in Vermont?
Alder prefers pH 4.4-7.2 and poorly (saturated >50% of year) drainage (USDA PLANTS). That sits in the common-ground band across Vermont soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Alder actually grow on my specific land in Vermont?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores alder 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 Vermont
State-level data is a sketch. Your Growable Ground report scores alder against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Vermont alder averages can't show:
We read public map data around Vermont — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Vermont alder 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
Last updated: