Yes — Strong Match
common milkweed (zones 3-9) covers every zone Maine contains (3b-7a), so hardiness is not what limits it anywhere in the state.
Common Milkweed in Maine — the short answer
Common Milkweed in Maine: hardy in zones 3–9, full sun, against a state median of ~182 frost-free days.
- Plant zones
- 3-9
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Maine zones
- 3b-7a
- USDA PHZM 2023
- Frost window
- Apr 16 - May 3 – Oct 10 - Oct 24
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 143 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Maine spans zones 3b-7a, 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 common milkweed against your parcel's actual hardiness, soil, and sun.
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Maine is not one climate
Maine’s winter-low ladder runs across 16 counties, from zone 4 in Aroostook County to zone 6 in Lincoln County. That is 20°F between the two counties’ average coldest night — the difference between common milkweed overwintering in the ground and coming under cover.
The middle half of 16 counties runs 4.5–5.5 zones, with a median of 5.5 zones — a 2-zone span end to end.
Measured across 16 Maine counties. USDA PHZM 2023, per county. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in Maine Fits Best
Even within Maine's zones 3b-7a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for common milkweed (USDA PHZM 2023):
Zone Comparison
Common Milkweed Needs
- USDA Zones: 3-9
- Frost-Free Days: 120+
- Sun: Full Sun
- Mature size: 5 ft tall
- Picking window: ~45 days of harvest
- Drought tolerance: High
Maine Has
- USDA Zones: 3b-7a
- Last Hard Freeze (28°F): Apr 16 - May 3
- First Hard Freeze (28°F): Oct 10 - Oct 24
- Annual Rainfall: 36-50 inches
- Common Soils: Glacial till, Sandy loam, Rocky loam
Plant Zone Range (zones 3-9)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Common Milkweed in Maine
The frost window
Across Maine, the last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 191 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
Maine runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for common milkweed, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether common milkweed is a permanent planting or a replant-every-spring crop for you turns on your own zone within Maine; check its hardiness range against that before treating it as long-lived ground.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. 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 common milkweed survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Common Milkweed wants 120+ frost-free days; a typical Maine site sees ~182 (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
Common Milkweed tolerates a wide pH range (pH 4.5-7.5) — 3 units, acid ground through alkaline — so soil acidity is rarely what limits it in Maine. 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 5 and 7 — worth knowing before you decide whether a Maine soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Maine site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Maine soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Common Milkweed in Maine
Zone compatibility tells you about winter cold survival — but Maine growers also need to think about:
Very short growing season (100-140 frost-free days)
Rocky glacial soils require significant clearing
Harsh winters with heavy snow and ice
What to actually do about these — and the constraints that apply to every Maine grower, not just common milkweed — is covered on the Maine growing guide.
Timing shifts within Maine
Common Milkweed needs about 120 days of frost-free season to complete its cycle. Even Franklin County — Maine’s shortest season at 143 frost-free days — clears that by 23 days, so season length isn’t the constraint anywhere in Maine. What varies is your own parcel.
Across Maine’s 16 counties the frost-free season runs from 143 days in Franklin County to 222 days in Knox County — a spread of 79 days, which is why a single statewide planting date misleads. The median Maine county sees 182 frost-free days, leaving common milkweed about 62 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"). Common Milkweed's 120-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
Common Milkweed draws honeybees, native bees, butterflies, and moths (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, common milkweed can only work that bloom inside Maine's frost window — roughly 182 days, opening after the last 28°F freeze (Apr 16 - May 3) and closing at the first (Oct 10 - Oct 24), per NOAA Regional Climate Centers ACIS, 1991-2020.
Maine Cooperative Extension
For Maine-specific cultivar recommendations, planting calendars, and pest pressure for common milkweed, the canonical source is UMaine Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Common Milkweed native to Maine?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Common Milkweed as native to Maine. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Common Milkweed in Maine
When can I plant Common Milkweed in Maine?
Maine's last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Common Milkweed, so this page does not state whether it overwinters in Maine 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 Common Milkweed grown in across Maine?
Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Common Milkweed carries a range of zones 3-9, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Maine site have?
A typical Maine site sees ~182 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Common Milkweed needs 120+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Common Milkweed native to Maine?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Common Milkweed as native to Maine. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Common Milkweed in Maine?
Common Milkweed tolerates pH 4.5-7.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Maine site — amend for drainage and organic matter first.
Will Common Milkweed actually grow on my specific land in Maine?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores common milkweed 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 Maine
State-level data is a sketch. Your Growable Ground report scores common milkweed against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Maine common milkweed averages can't show:
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25+ data sources read at your address, not the Maine common milkweed average
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