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When to Plant Echinacea in Jefferson County, OR

Jefferson County, Oregon Zone 7a May

May to-do list for Jefferson County, Oregon

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

Avg. last frost June 9
Avg. first frost September 19
Soil temp (4") 61°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
To set up a strong June, finish these tasks
  • Transplants going out: echinacea

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

Jefferson County, Oregon is in USDA Zone 7a. The average last spring frost is June 9 and the first fall frost is September 19, giving you a growing season of approximately 102 days.

At an elevation of 21 feet, Jefferson County receives approximately 36.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 79°F, so choose short-season varieties of Echinacea to ensure they mature before fall.

Jefferson County, OR (Zone 7a) Short season
102 days
Last Spring Frost June 9
102 growing days
First Fall Frost September 19

Jefferson County Soil Profile

Soil Type

Silt Loam

Soil pH

5.3-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (237 days to spare)
Transplant: Jun 6 🍅 Harvest: Oct 10 – Jan 16
Recommended (50%) ✓ Fits season (236 days to spare)
Transplant: Jun 16 🍅 Harvest: Oct 20 – Jan 26
Safe Start (90%) ✓ Fits season (240 days to spare)
Transplant: Jun 29 🍅 Harvest: Nov 2 – Feb 8

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 Jefferson County

How your county's soil matches Echinacea's growing requirements.

Soil pH

Your soil pH (5.3–6.7) overlaps with Echinacea's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Jefferson County is excellent for Echinacea — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.0%) — Echinacea will thrive.

How to Plant Echinacea

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Echinacea

Echinacea 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 Needs Rainfall You Supplement Action
Jan 4.8" 0" ❄️ Dormant
Feb 3.7" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 1.8" 0" ❄️ Dormant
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 0.5" 1.7" 🚿 Regular watering
Aug 2.2" 0.6" 1.6" 🚿 Regular watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 3.2" 0" ❄️ Dormant
Nov 6.1" 0" ❄️ Dormant
Dec 5.5" 0" ❄️ Dormant

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

Echinacea 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 needs ~1,388 GDD — county provides 943 GDD May not mature

Echinacea Planting Timeline — Jefferson County, OR

Echinacea Planting Calendar

Activity When Date Range
Transplant Outdoors June 16 Jun 16 – Jun 30
Harvest October 20 Oct 20 – Jan 26

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January Harvest
February
March
April
May
June Transplant Outdoors
July
August
September
October Harvest
November Harvest
December Harvest

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

102 days in Jefferson County

Growing Tips for Echinacea in Jefferson County

Direct sow Echinacea outdoors after June 09 in Jefferson County when soil has warmed and frost danger has passed.

Your 102.0-day growing season in Jefferson County is tight for Echinacea (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Echinacea in Jefferson County, OR?

Jefferson County is in Zone 7a with an average last frost of June 9. Plan your Echinacea planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jefferson County, OR?

Jefferson County, Oregon is in USDA Hardiness Zone 7a. The average last spring frost is June 9 and first fall frost is September 19.

🌱

Your Jefferson County Garden Planner — Free

A 24-page printable planner built for Jefferson County (Zone 7a). 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 Jefferson County, OR. Local conditions may vary. Last updated: May 2026.

Sources & credits

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