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When to Plant Bee Balm in Rock County, MN

Bee balm is a native perennial herb with shaggy, scarlet flower heads that attract hummingbirds, bees, and butterflies. Its leaves make an aromatic tea reminiscent of Earl Grey.

Rock County, Minnesota is in USDA Zone 4b. The average last spring frost is May 2 and the first fall frost is October 2, giving you a growing season of approximately 153 days.

At an elevation of 916 feet, Rock County receives approximately 32.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Bee Balm to ensure they mature before fall.

Rock County, MN (Zone 4b) Moderate season
153 days
Last Spring Frost May 2
153 growing days
First Fall Frost October 2

Rock County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 4 🍅 Harvest: Aug 3 – Sep 28
Recommended (50%) ✗ May not fit
Transplant: May 9 🍅 Harvest: Aug 8 – Oct 3
Safe Start (90%) ✗ May not fit
Transplant: May 23 🍅 Harvest: Aug 22 – Oct 17

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
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 181 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Bee Balm needs ~1,208 GDD — county provides 1,759 GDD Excellent fit

Bee Balm Planting Timeline โ€” Rock County, MN

Bee Balm Planting Calendar

Activity When Date Range
Transplant Outdoors May 9 May 9 โ€“ May 23
Harvest August 8 Aug 8 โ€“ Oct 3

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 โ€”
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

90โ€“120 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4b

Growing Season

153 days

Growing Tips for Rock County

Start from seed, divisions, or transplants. Provide good air circulation to prevent powdery mildew. Deadhead spent flowers for reblooming. Divide clumps every 3 years.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Bee Balm in Rock County, MN?

Rock County is in Zone 4b with an average last frost of May 2. Plan your Bee Balm planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Rock County, MN?

Rock County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is May 2 and first fall frost is October 2.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Rock 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 Rock County, MN. Local conditions may vary. Last updated: April 2026.