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When to Plant Echinacea (Purple Coneflower) in Carbon County, UT

Carbon County, Utah Zone 6a June

Your June game plan for Carbon County, Utah

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 17
Avg. first frost September 27
Soil temp (4") 54°F
Watering Critical
Pest pressure High
Daylight 14.8 hrs
Looking ahead to July
  • Starting indoors: echinacea (purple coneflower)

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Echinacea purpurea (Purple Coneflower) is a long-lived native prairie perennial and one of the most valuable pollinator plants in North American gardens. Its distinctive daisy-like blooms — swept-back lavender-pink petals surrounding a spiny orange-brown cone — attract bees, butterflies, and goldfinches from summer into fall. Drought-tolerant once established, adaptable to average soils, and impressively long-lived; mature clumps bloom reliably for decades.

Carbon County, Utah is in USDA Zone 6a. The average last spring frost is May 17 and the first fall frost is September 27, giving you a growing season of approximately 133 days.

At an elevation of 5,755 feet, Carbon County receives approximately 14.2 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Echinacea (Purple Coneflower) to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Echinacea (Purple Coneflower) successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting
Carbon County, UT (Zone 6a) Short season
133 days
Last Spring Frost May 17
133 growing days
First Fall Frost September 27
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Carbon County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.3

Drainage

Well Drained

Echinacea (Purple Coneflower) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 5 Transplant: May 21 🌸 Bloom: Aug 13 – Nov 19
Recommended (50%) ✗ May not fit
Start indoors: Mar 15 Transplant: May 31 🌸 Bloom: Aug 23 – Nov 29
Safe Start (90%) ✗ May not fit
Start indoors: Apr 6 Transplant: Jun 22 🌸 Bloom: Sep 14 – Dec 21

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.

Soil Compatibility in Carbon County

How your county's soil matches Echinacea (Purple Coneflower)'s growing requirements.

Soil pH

Your soil pH (6.4–8.3) is more alkaline than Echinacea (Purple Coneflower) prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Carbon County is excellent for Echinacea (Purple Coneflower) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Echinacea (Purple Coneflower).

How to Plant Echinacea (Purple Coneflower)

0.3"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Echinacea (Purple Coneflower)

2
successive plantings in your 133-day season

Sow every 8 weeks. Last sowing by Jun 29 to harvest before frost.

Echinacea (Purple Coneflower) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 73 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Echinacea (Purple Coneflower)

Echinacea (Purple Coneflower) needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Echinacea (Purple Coneflower) Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.2" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 2.2" 1.8" 0.4" 💧 Light watering
Jun 2.2" 1.1" 1.1" 🚿 Regular watering
Jul 2.2" 1.3" 0.9" 💧 Light watering
Aug 2.2" 1.3" 0.9" 💧 Light watering
Sep 2.2" 1.1" 1.1" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Echinacea (Purple Coneflower) Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Echinacea (Purple Coneflower) needs ~1,040 GDD — county provides 1,729 GDD Excellent fit

Echinacea (Purple Coneflower) Planting Timeline — Carbon County, UT

Echinacea (Purple Coneflower) Planting Calendar

Activity When Date Range
Start Indoors March 15 Mar 15 – Mar 29
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 31 May 31 – Jun 21
Bloom August 23 Aug 23 – Nov 29

Plant 0.3" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July
August Bloom
September Bloom
October Bloom
November Bloom
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6a

📆 Growing Season

133 days in Carbon County

Growing Tips for Echinacea (Purple Coneflower) in Carbon County

Direct sow Echinacea (Purple Coneflower) outdoors after May 17 in Carbon County when soil has warmed and frost danger has passed.

Common pests for Echinacea (Purple Coneflower) in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

Carbon County receives only 14" of rain annually. Echinacea (Purple Coneflower) needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 8–10 weeks before last frost or direct-sow in fall for natural cold stratification. Seeds require 4–8 weeks of cold moist stratification (or fall sowing) for best germination. Transplant when night temps stay above 50°F. Full sun is essential for heavy bloom. Avoid over-fertilizing — lean soil produces more compact, floriferous plants. Deadhead for continuous bloom but leave some cones standing in fall for goldfinch seed harvest. Year 2+ plants bloom most heavily; first-year transplants may produce limited flowers. Divide congested clumps every 3–4 years in early spring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Echinacea (Purple Coneflower) in Carbon County, UT?

Carbon County is in Zone 6a with an average last frost of May 17. Plan your Echinacea (Purple Coneflower) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Carbon County, UT?

Carbon County, Utah is in USDA Hardiness Zone 6a. The average last spring frost is May 17 and first fall frost is September 27.

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Your Carbon County Garden Planner — Free

A 22-page printable planner built for Carbon County (Zone 6a). 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 Carbon County, UT. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.