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When to Plant Comfrey in Natrona County, WY

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

Natrona County, Wyoming is in USDA Zone 4b. The average last spring frost is May 19 and the first fall frost is September 23, giving you a growing season of approximately 127 days.

At an elevation of 6,332 feet, Natrona County receives approximately 13.7 inches of rainfall annually with predominantly loam soil. Summer highs average 83ยฐF, 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.

Natrona County, WY (Zone 4b) Short season
127 days
Last Spring Frost May 19
127 growing days
First Fall Frost September 23

Natrona County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29
Recommended (50%) ✗ May not fit
Transplant: May 26 🍅 Harvest: Jul 28 – Oct 6
Safe Start (90%) ✗ May not fit
Transplant: Jun 9 🍅 Harvest: Aug 11 – Oct 20

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 742 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Comfrey needs ~919 GDD — county provides 1,555 GDD Excellent fit

Comfrey Planting Timeline โ€” Natrona County, WY

Comfrey Planting Calendar

Activity When Date Range
Transplant Outdoors May 26 May 26 โ€“ Jun 9
Harvest July 28 Jul 28 โ€“ Oct 6

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

60โ€“90 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

127 days

Growing Tips for Natrona 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

Level Up Your Garden

Frequently Asked Questions

When should I plant Comfrey in Natrona County, WY?

Natrona County is in Zone 4b with an average last frost of May 19. Plan your Comfrey planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Natrona County, WY?

Natrona County, Wyoming is in USDA Hardiness Zone 4b. The average last spring frost is May 19 and first fall frost is September 23.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Natrona County gardeners in Zone 4b organize planting dates, track what's growing, and never miss a planting window.

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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 Natrona County, WY. Local conditions may vary. Last updated: April 2026.