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When to plant Comfrey in Roseau County County,

Plant Comfrey in Roseau County County during the brief May 28–June 11 window. With 124 frost-free days, fall plantings can't mature before September 22.

When to Plant Comfrey in Roseau County, MN

Comfrey is a vigorous perennial herb valued as a dynamic accumulator of nutrients. Its leaves make excellent mulch, compost activator, and liquid fertilizer.

Roseau County, Minnesota is in USDA Zone 3b. The average last spring frost is May 21 and the first fall frost is September 22, giving you a growing season of approximately 124 days.

At an elevation of 655 feet, Roseau County receives approximately 32 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Comfrey to ensure they mature before fall.

Roseau County, MN (Zone 3b) Short season
124 days
Last Spring Frost May 21
124 growing days
First Fall Frost September 22

Roseau County Soil Profile

Soil Type

Silt Loam

Soil pH

6.0-7.0

Drainage

Well Drained

Comfrey Planting Timeline — Roseau County, MN

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 28 May 28 – Jun 11
Harvest July 30 Jul 30 – Oct 1

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July Harvest
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 3b

📆 Growing Season

124 days in Roseau County

Growing Tips for Roseau County

Plant root cuttings 2 inches deep. Choose Bocking 14 variety to prevent self-seeding. Cut leaves 3-4 times per season for mulch or compost. Avoid planting near pathways as it spreads.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Comfrey in Roseau County, MN?

Roseau County is in Zone 3b with an average last frost of May 21. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Roseau County, MN?

Roseau County, Minnesota is in USDA Hardiness Zone 3b. The average last spring frost is May 21 and first fall frost is September 22.

When should I plant Comfrey in Roseau County County, ?

In Roseau County County, , plant Comfrey after the last frost (around May 21) and before the first frost (around September 22). Best results when soil holds above 50°F.

What growing zone is Roseau County County, for Comfrey?

Roseau County County sits in USDA Zone 3b. Comfrey grows reliably in zones 3a through 9b, so it's a good fit here.

Can Comfrey grow in Roseau County County's climate?

Yes — Comfrey grows well in Roseau County County's temperate climate. Roseau County County averages a 124-day frost-free season, with last frost around May 21 and first frost around September 22.

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Your Roseau County Garden Planner — Free

A 22-page printable planner built for Roseau County (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Roseau County, MN. Local conditions may vary. Last updated: June 2026.

Sources & credits

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