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When to Plant Echinacea in Summit County, CO

Echinacea (purple coneflower) is a native prairie perennial valued for its immune-supporting properties and beautiful daisy-like flowers that attract pollinators.

Summit County, Colorado is in USDA Zone 4a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.

At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81ยฐF, so choose short-season varieties of Echinacea to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Echinacea successfully. Mulch heavily to conserve soil moisture.

Summit County, CO (Zone 4a) Very short season
80 days
Last Spring Frost June 16
80 growing days
First Fall Frost September 4

Summit County Soil Profile

Soil Type

Loam

Soil pH

6.8-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 17 🍅 Harvest: Oct 21 – Nov 11
Recommended (50%) ✗ May not fit
Transplant: Jun 23 🍅 Harvest: Oct 27 – Nov 17
Safe Start (90%) ✗ May not fit
Transplant: Jul 3 🍅 Harvest: Nov 6 – Nov 27

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
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Echinacea needs ~1,612 GDD — county provides 860 GDD May not mature

Echinacea Planting Timeline โ€” Summit County, CO

Echinacea Planting Calendar

Activity When Date Range
Transplant Outdoors June 23 Jun 23 โ€“ Jul 7
Harvest October 27 Oct 27 โ€“ Nov 17

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 โ€”
June Transplant Outdoors
July Transplant Outdoors
August โ€”
September โ€”
October Harvest
November Harvest
December โ€”

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

120โ€“180 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 4a

Growing Season

80 days

Growing Tips for Summit County

Start seeds indoors 8-10 weeks before last frost or direct sow in fall for spring germination. Seeds need cold stratification. Deadhead to prolong blooming or leave seed heads for birds.

Companion Planting

Good Companions

Level Up Your Garden

Frequently Asked Questions

When should I plant Echinacea in Summit County, CO?

Summit County is in Zone 4a with an average last frost of June 16. Plan your Echinacea planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Summit County, CO?

Summit County, Colorado is in USDA Hardiness Zone 4a. The average last spring frost is June 16 and first fall frost is September 4.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Summit County gardeners in Zone 4a 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 Summit County, CO. Local conditions may vary. Last updated: April 2026.