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

Jerome County County sits in cold Zone 6b. Plant Echinacea (Purple Coneflower) May 17–June 7 for the single annual harvest; the October 4 first frost closes the window.

When to Plant Echinacea (Purple Coneflower) in Jerome County, ID

Jerome County, Idaho Zone 6b June

Your June gardening checklist

Each item below is timed to Jerome County, Idaho's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 10
Avg. first frost October 4
Soil temp (4") 55°F
Watering Critical
Pest pressure High
Daylight 15.1 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.

Jerome County, Idaho is in USDA Zone 6b. The average last spring frost is May 10 and the first fall frost is October 4, giving you a growing season of approximately 147 days.

At an elevation of 6,306 feet, Jerome County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°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
Jerome County, ID (Zone 6b) Short season
147 days
Last Spring Frost May 10
147 growing days
First Fall Frost October 4
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Jerome County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.9

Drainage

Well Drained

Echinacea (Purple Coneflower) Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 27 Transplant: May 8 🌸 Bloom: Jul 24 – Nov 13
Recommended (50%) ✗ May not fit
Start indoors: Mar 8 Transplant: May 17 🌸 Bloom: Aug 2 – Nov 22
Safe Start (90%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 11 🌸 Bloom: Aug 27 – Dec 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.

Soil Compatibility in Jerome County

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

Soil pH

Your soil pH (6.8–7.9) 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 Jerome 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 147-day season

Sow every 8 weeks. Last sowing by Jul 06 to harvest before frost.

Echinacea (Purple Coneflower) Water Budget

Plant needs
0.5″/week
Rainfall provides
0.4″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 179 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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 0.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.6" 0" ❄️ Dormant
May 2.2" 1.5" 0.7" 💧 Light watering
Jun 2.2" 1" 1.2" 🚿 Regular watering
Jul 2.2" 1.2" 1" 💧 Light watering
Aug 2.2" 1.3" 0.9" 💧 Light watering
Sep 2.2" 1.1" 1.1" 🚿 Regular watering
Oct 2.2" 1.1" 1.1" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Jerome 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 ~1,100 GDD — county provides 2,021 GDD Excellent fit

Echinacea (Purple Coneflower) Planting Timeline — Jerome County, ID

Echinacea (Purple Coneflower) Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors May 17 May 17 – May 31
Direct Sow May 17 May 17 – Jun 7
Bloom August 2 Aug 2 – Nov 22

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 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 6b

📆 Growing Season

147 days in Jerome County

Growing Tips for Echinacea (Purple Coneflower) in Jerome County

Direct sow Echinacea (Purple Coneflower) outdoors after May 10 in Jerome 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.

Jerome 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 Jerome County, ID?

Jerome County is in Zone 6b with an average last frost of May 10. Plan your Echinacea (Purple Coneflower) planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jerome County, ID?

Jerome County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 10 and first fall frost is October 4.

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

In Jerome County County, , plant Echinacea (Purple Coneflower) after the last frost (around May 10) and before the first frost (around October 4). Best results when soil holds above 50°F.

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

Jerome County County sits in USDA Zone 6b. Echinacea (Purple Coneflower) grows reliably in zones 3a through 9b, so it's a good fit here.

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

Yes — Echinacea (Purple Coneflower) grows well in Jerome County County's temperate climate. Jerome County County averages a 147-day frost-free season, with last frost around May 10 and first frost around October 4.

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Your Jerome County Garden Planner — Free

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

Sources & credits

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