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When to plant Comfrey in Glacier County, MT

Glacier County's short 119-day growing season means one Comfrey planting between May 29 and June 12. No fall crop in Zone 4b.

When to Plant Comfrey in Glacier County, MT

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

Glacier County, Montana is in USDA Zone 4b. The average last spring frost is May 22 and the first fall frost is September 18, giving you a growing season of approximately 119 days.

At an elevation of 8,147 feet, Glacier County receives approximately 13.3 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Comfrey to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Comfrey successfully. Mulch heavily to conserve soil moisture.

Glacier County, MT (Zone 4b) Short season
119 days
Last Spring Frost May 22
119 growing days
First Fall Frost September 18

Glacier County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.1

Drainage

Well Drained

Monthly Watering Guide for Comfrey

Comfrey needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Comfrey Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 4.3" 1.6" 2.7" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.3" 3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Glacier County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Comfrey Planting Timeline — Glacier County, MT

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 29 May 29 – Jun 12
Harvest July 31 Jul 31 – Oct 9

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 4b

📆 Growing Season

119 days in Glacier County

Growing Tips for Glacier 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 Glacier County, MT?

Glacier County is in Zone 4b with an average last frost of May 22. Plan your Comfrey planting based on this frost date — see the calendar above for exact timing.

What planting zone is Glacier County, MT?

Glacier County, Montana is in USDA Hardiness Zone 4b. The average last spring frost is May 22 and first fall frost is September 18.

When should I plant Comfrey in Glacier County, MT?

In Glacier County, MT, plant Comfrey after the last frost (around May 22) and before the first frost (around September 18). Best results when soil holds above 50°F.

What growing zone is Glacier County, MT for Comfrey?

Glacier County sits in USDA Zone 4b. Comfrey grows reliably in zones 3a through 9b, so it's a good fit here.

Can Comfrey grow in Glacier County's climate?

Yes — Comfrey grows well in Glacier County's temperate climate. Glacier County averages a 119-day frost-free season, with last frost around May 22 and first frost around September 18.

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Your Glacier County Garden Planner — Free

A 22-page printable planner built for Glacier County (Zone 4b). 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 Glacier County, MT. Local conditions may vary. Last updated: July 2026.

Sources & credits

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