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When to plant Feverfew in Sublette, IL

In Sublette, Feverfew is a single-season spring crop — there's no second fall window. Plant April 29–May 13 for an 120-day harvest, finishing well before the October 14 first frost.

When to Plant Feverfew in Sublette, IL

Lee County, Illinois Zone 5b June

June in Lee County, Illinois — your action list

A quick June briefing for Lee County, Illinois gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 22
Avg. first frost October 14
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 15 hrs
A few tasks this June that'll pay off in July
  • First harvests: 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.

Sublette, Illinois is in USDA Zone 5b. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 1,010 feet, Lee County receives approximately 33.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Feverfew to ensure they mature before fall.

Sublette, IL (Zone 5b) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14

Sublette Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.9

Drainage

Well Drained

Feverfew Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Transplant: Apr 24 🍅 Harvest: Jul 24 – Oct 9
Recommended (50%) ✓ Fits season (0 days to spare)
Transplant: Apr 29 🍅 Harvest: Jul 29 – Oct 14
Safe Start (90%) ✓ Fits season (1 days to spare)
Transplant: May 12 🍅 Harvest: Aug 11 – Oct 27

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 Sublette

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

Soil pH

Your soil pH (6.3–6.9) is within Feverfew's preferred range (6.0–7.0).

Soil Texture

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

Drainage

Drainage is adequate for Feverfew.

Organic Matter

Organic matter is excellent (4.8%) — Feverfew will thrive.

How to Plant Feverfew

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

Feverfew Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 4.4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.2" 0" ✅ Rainfall sufficient
Jul 2.2" 3.3" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 2.9" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.7" 0" ❄️ Dormant
Dec 1.8" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Lee 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 ~1,365 GDD — county provides 2,275 GDD Excellent fit

Feverfew Planting Timeline — Sublette, IL

Feverfew Planting Calendar

Activity When Date Range
Transplant Outdoors April 29 Apr 29 – May 13
Harvest July 29 Jul 29 – Oct 14

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

Month-by-Month Timeline

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

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: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

175 days in Lee County

Growing Tips for Feverfew in Sublette

Direct sow Feverfew outdoors after April 22 in Lee County when soil has warmed and frost danger has passed.

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 →

When should I plant Feverfew in Sublette, IL?

In Sublette, IL, plant Feverfew after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Sublette, IL for Feverfew?

Sublette sits in USDA Zone 5b. Feverfew grows reliably in zones 5a through 9b, so it's a good fit here.

Can Feverfew grow in Sublette's climate?

Yes — Feverfew grows well in Sublette's temperate climate. Sublette averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.

🌱

Your Lee County Garden Planner — Free

A 22-page printable planner built for Lee 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 Lee County, IL. Local conditions may vary. Last updated: June 2026.