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When to Plant Mulberries in Jefferson County, CO

Mulberries are fast-growing, long-lived trees that produce abundant sweet-tart berries over an extended harvest period. The berries resemble elongated blackberries.

Jefferson County, Colorado is in USDA Zone 5b. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 5,376 feet, Jefferson County receives approximately 22.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84ยฐF, so choose short-season varieties of Mulberries to ensure they mature before fall.

Jefferson County, CO (Zone 5b) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26

Jefferson County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 24
Recommended (50%) ✓ Fits season
Transplant: Jun 4
Safe Start (90%) ✓ Fits season
Transplant: Jul 1

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
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 424 gal / 100 sq ft
Drought risk

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

Mulberries needs ~16,608 GDD — county provides 1,755 GDD May not mature

Mulberries Planting Timeline โ€” Jefferson County, CO

Mulberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 โ€“ Jun 18

ยท 120" apart ยท Rows 144" apart

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate โ€” regular watering

Days to Maturity

730โ€“1825 days

Soil pH

5.5 โ€“ 7

USDA Zone

Zone 5b

Growing Season

135 days

Growing Tips for Jefferson County

Plant away from driveways and patios as fallen berries stain. Minimal pruning is needed. Harvest by shaking branches over a tarp. Birds love mulberries so plant extra.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Mulberries in Jefferson County, CO?

Jefferson County is in Zone 5b with an average last frost of May 14. Plan your Mulberries planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Jefferson County, CO?

Jefferson County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Jefferson County gardeners in Zone 5b 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 Jefferson County, CO. Local conditions may vary. Last updated: April 2026.