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When to Plant Feverfew in Jefferson County, OR

Jefferson County, Oregon Zone 7a May

May in the garden — Jefferson County, Oregon

Here's what deserves your attention in Jefferson County, Oregon this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost June 9
Avg. first frost September 19
Soil temp (4") 61°F
Watering High
Pest pressure Low
Daylight 14.6 hrs
Get ahead of June
  • Transplants going out: feverfew

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Feverfew is a bushy perennial herb with small daisy-like flowers and aromatic leaves. It has been used traditionally for headache relief and is a cheerful garden plant.

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 Feverfew 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) ✗ May not fit
Transplant: Jun 6 🍅 Harvest: Sep 5 – Nov 21
Recommended (50%) ✗ May not fit
Transplant: Jun 16 🍅 Harvest: Sep 15 – Dec 1
Safe Start (90%) ✗ May not fit
Transplant: Jun 29 🍅 Harvest: Sep 28 – Dec 14

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 Feverfew's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Feverfew

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 Feverfew

Feverfew 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 Feverfew 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.

Feverfew 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.

Feverfew needs ~971 GDD — county provides 943 GDD Tight fit

Feverfew Planting Timeline — Jefferson County, OR

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors June 16 Jun 16 – Jun 30
Harvest September 15 Sep 15 – Dec 1

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

102 days in Jefferson County

Growing Tips for Feverfew in Jefferson County

Direct sow Feverfew 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 Feverfew (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Start seeds indoors or direct sow on the soil surface. Deadhead regularly to prevent aggressive self-seeding. Divide clumps every 2-3 years to maintain vigor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Feverfew in Jefferson County, OR?

Jefferson County is in Zone 7a with an average last frost of June 9. Plan your Feverfew 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.