Generally — Most Areas
whorled milkweed (zones 3-9) partially overlaps with Maryland (5b-8a). It can grow in zones 5-8 within the state.
Your yard isn't the whole zone.
Maryland spans zones 5b-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 whorled milkweed 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
Whorled Milkweed Needs
- USDA Zones: 3-9
- Soil pH: 5.5 - 7.5
- Sun: Full Sun
- Drainage: well (dry spells)
Maryland Has
- USDA Zones: 5b-8a
- Last Frost: Mar 25 - May 5
- First Frost: Oct 5 - Nov 5
- Annual Rainfall: 36-48 inches
- Common Soils: Silt loam, Clay, Sandy loam (Eastern Shore)
Plant Zone Range (zones 3-9)
Preferred Soil pH
Plant data: USDA PLANTS Database / plant_species_v5.csv. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Whorled Milkweed in Maryland
The frost window
Across Maryland, the last spring frost clears between Mar 25 and May 5, and the first fall frost lands between Oct 5 and Nov 5 (NOAA Climate Normals 1991-2020). Counting from the latest last frost to the earliest first frost, that's a 153-day window you can count on — up to 225 days on a mild site in a kind year.
Establishment timing
As a long-lived plant, whorled milkweed isn't racing the calendar to a harvest date. Plant it in spring once the last-frost window passes so roots settle in through the full season, or in early fall while the soil still holds summer warmth.
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.
Soil + Drainage Fit
Whorled Milkweed likes near-neutral soil (pH 5.5-7.5). That's the common-ground band across Maryland's silt loam and clay — a soil test confirms it for your site. Drainage matters: this plant wants well (dry spells). If your Maryland site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH and drainage requirements from USDA PLANTS Database. Maryland soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Whorled Milkweed in Maryland — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 3-9 (USDA PLANTS Database)
- State Zones: 5b-8a (USDA ARS PHZM 2023)
- Growing Season: Mar 25 - May 5 to Oct 5 - Nov 5 (NOAA Climate Normals)
What Else to Consider
Zone compatibility tells you about winter cold survival — but Maryland growers also need to think about:
Heavy Piedmont clay drains poorly
A raised bed today, compost every fall — Piedmont clay becomes an asset once the drainage is yours.
Humidity and heat in summer promote disease
Morning watering at the base, room to breathe between plants, resistant varieties — the humid-summer basics, per your extension.
Deer pressure in suburban areas is extreme
A tall fence is the answer that holds; for everything outside it, lean toward the plants deer reliably skip.
Pollinator + Wildlife Value
Whorled Milkweed draws pollinators (high value, USDA PLANTS Database). Planting it near vegetable beds can lift fruit set on neighboring crops.
Maryland Cooperative Extension
For Maryland-specific cultivar recommendations, planting calendars, and pest pressure for whorled milkweed, the canonical source is University of Maryland Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Whorled Milkweed native to Maryland?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Whorled Milkweed as native to Maryland. 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 Whorled Milkweed in Maryland
When can I plant Whorled Milkweed in Maryland?
Maryland's last spring frost clears between Mar 25 and May 5, and the first fall frost lands between Oct 5 and Nov 5 (NOAA Climate Normals 1991-2020). Whorled Milkweed is a long-lived planting, so target spring just after your local last frost — or early fall while the soil holds warmth — and let it establish through the season.
What hardiness zone is Whorled Milkweed grown in across Maryland?
Maryland spans USDA hardiness zones 5b-8a (USDA ARS PHZM 2023). Whorled 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 Maryland site have?
A typical Maryland site sees ~190 frost-free days per year (derived from NOAA Climate Normals 1991-2020). Whorled Milkweed 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.
Is Whorled Milkweed native to Maryland?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Whorled Milkweed as native to Maryland. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Whorled Milkweed in Maryland?
Whorled Milkweed prefers pH 5.5-7.5 and well (dry spells) drainage (USDA PLANTS Database). That sits in the common-ground band across Maryland soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Whorled Milkweed actually grow on my specific land in Maryland?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores whorled 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 Maryland
State-level data is a sketch. Your Growable Ground report scores whorled milkweed against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds