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When to plant Echinacea (Purple Coneflower) in Weld County County,

Echinacea (Purple Coneflower) planted in Weld County County between May 16 and June 6 matures in 90 days — well before the October 7 first frost.

When to Plant Echinacea (Purple Coneflower) in Weld County, CO

Weld County, Colorado Zone 5b June

Your June planting checklist for Weld County, Colorado

Your Weld County, Colorado garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 2
Avg. first frost October 7
Soil temp (4") 50°F
Watering High
Pest pressure High
Daylight 14.9 hrs
A few tasks this June that'll pay off in 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.

Weld County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 7, giving you a growing season of approximately 158 days.

At an elevation of 6,992 feet, Weld County receives approximately 18.8 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Echinacea (Purple Coneflower) during the growing season. 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
Weld County, CO (Zone 5b) Moderate season
158 days
Last Spring Frost May 2
158 growing days
First Fall Frost October 7

Weld County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.1

Drainage

Well Drained

Echinacea (Purple Coneflower) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 23 Transplant: May 11 🌸 Bloom: Aug 3 – Nov 2
Recommended (50%) ✗ May not fit
Start indoors: Feb 28 Transplant: May 16 🌸 Bloom: Aug 8 – Nov 7
Safe Start (90%) ✗ May not fit
Start indoors: Mar 17 Transplant: Jun 2 🌸 Bloom: Aug 25 – Nov 24

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 Weld County

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

Soil pH

Your soil pH (6.6–8.1) 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 Weld County is excellent for Echinacea (Purple Coneflower) — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). 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 158-day season

Sow every 8 weeks. Last sowing by Jul 09 to harvest before frost.

Echinacea (Purple Coneflower) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
Watering frequency Only during dry spells
Season total 0 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 1.4" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 1.4" 0.8" 💧 Light watering
Jul 2.2" 1.7" 0.5" 💧 Light watering
Aug 2.2" 1.8" 0.4" 💧 Light watering
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 2.2" 1.7" 0.5" 💧 Light watering
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Weld 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 ~1,220 GDD — county provides 2,409 GDD Excellent fit

Echinacea (Purple Coneflower) Planting Timeline — Weld County, CO

Echinacea (Purple Coneflower) Planting Calendar

Activity When Date Range
Start Indoors February 28 Feb 28 – Mar 14
Transplant Outdoors May 16 May 16 – May 30
Direct Sow May 16 May 16 – Jun 6
Bloom August 8 Aug 8 – Nov 7

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

Month-by-Month Timeline

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

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 5b

📆 Growing Season

158 days in Weld County

Growing Tips for Echinacea (Purple Coneflower) in Weld County

Direct sow Echinacea (Purple Coneflower) outdoors after May 02 in Weld 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.

Weld County receives only 19" 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 Weld County, CO?

Weld County is in Zone 5b with an average last frost of May 2. Plan your Echinacea (Purple Coneflower) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Weld County, CO?

Weld County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 7.

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

In Weld County County, , plant Echinacea (Purple Coneflower) after the last frost (around May 2) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Weld County County, for Echinacea (Purple Coneflower)?

Weld County County sits in USDA Zone 5b. Echinacea (Purple Coneflower) grows reliably in zones 3a through 9b, so it's a good fit here.

Can Echinacea (Purple Coneflower) grow in Weld County County's climate?

Yes — Echinacea (Purple Coneflower) grows well in Weld County County's temperate climate. Weld County County averages a 158-day frost-free season, with last frost around May 2 and first frost around October 7.

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Your Weld County Garden Planner — Free

A 22-page printable planner built for Weld County (Zone 5b). 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 Weld County, CO. 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.