Conditional — Some Areas
persian clover (zones 6-10) 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
Persian Clover 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 persian clover 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 6-10 (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.
Persian Clover is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Vermont site runs ~163 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 persian clover against your land's actual frost dates, sun, and soil.
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Zone Comparison
Persian Clover Needs
- USDA Zones: 6-10
- Frost-Free Days: 90+
- Sun: Full Sun
- Mature size: 2 ft tall
- Drought tolerance: Low
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 6-10)
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 Persian Clover 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.
When to start the seed
Persian Clover is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Vermont's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 120 days to maturity (USDA PLANTS Database), counting from the last hard freeze it ripens with 38 days to spare even in Vermont's tightest freeze scenario — room for a later start or a second sowing.
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 persian clover survives winter in part of Vermont, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Persian Clover wants 90+ frost-free days; a typical Vermont site sees ~163 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
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
Persian Clover tolerates a wide pH range (pH 5-8) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Vermont. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 6 and 7.5 — worth knowing before you decide whether a Vermont soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Vermont site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
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 persian clover is the horizon its roots actually work, not the surface. That map unit, not the state average, decides how persian clover 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.
Persian Clover in Vermont — Quick Answer
- Verdict: Conditional — Some Areas
- Plant Zones: 6-10 (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)
- Days to Maturity: 120 days
What Else to Consider for Persian Clover 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 persian clover here specifically
Vermont's soils run mostly fine sandy loam (Spodosols), and whether that suits persian clover's pH 5.0–8.0 preference comes down to your exact parcel, not the statewide picture.
Pull your parcel's SSURGO map unit, test pH, and amend toward persian clover's 5.0–8.0 target before planting. How to handle it →
What to actually do about these — and the constraints that apply to every Vermont grower, not just persian clover — 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 persian clover to your county's window, not the statewide date.
Persian Clover needs about 90 days of frost-free season to complete its cycle. Even Essex County — Vermont’s shortest season at 146 frost-free days — clears that by 56 days, so season length isn’t the constraint anywhere in Vermont. 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"). Persian Clover's 90-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Persian Clover draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, persian clover can only work that bloom inside Vermont's frost window — roughly 163 days, opening after the last 28°F freeze (Apr 27 - May 5) and closing at the first (Oct 10 - Oct 17), per NOAA Regional Climate Centers ACIS, 1991-2020.
Vermont Cooperative Extension
For Vermont-specific cultivar recommendations, planting calendars, and pest pressure for persian clover, the canonical source is UVM Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Persian Clover native to Vermont?
No — the USDA PLANTS Database lists Persian Clover 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 Persian Clover in Vermont
When can I plant Persian Clover 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). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.
Can Persian Clover mature before first frost in Vermont?
Yes — Persian Clover matures in 120 days (USDA PLANTS Database), and Vermont's dependable hard-freeze-free window runs 158 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 38 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Persian Clover grown in across Vermont?
Vermont spans USDA hardiness zones 4a-6a (USDA ARS PHZM 2023). Persian Clover carries a range of zones 6-10, 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). Persian Clover needs 90+ 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 Essex, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Persian Clover native to Vermont?
No — the USDA PLANTS Database lists Persian Clover 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 Persian Clover in Vermont?
Persian Clover tolerates pH 5-8 and well (dry spells) drainage (Growable Ground Plant Database). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Vermont site — amend for drainage and organic matter first.
Will Persian Clover actually grow on my specific land in Vermont?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores persian clover 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 persian clover against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Vermont persian clover 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 persian clover average
Explore More
Growing guides for persian clover
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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