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When to Plant Rue in Iroquois County, IL

Iroquois County, Illinois Zone 5a April

April in the garden — Iroquois County, Illinois

April rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Iroquois County, Illinois.

Avg. last frost April 18
Avg. first frost October 13
Soil temp (4") 43°F
Watering Moderate
Pest pressure Low
Daylight 13.1 hrs
  1. Harden off and plant rue

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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Rue is a bitter, aromatic perennial herb with bluish-green foliage used historically in medicine and as a pest deterrent. Handle with care as its sap can cause skin irritation.

Iroquois County, Illinois is in USDA Zone 5a. The average last spring frost is April 18 and the first fall frost is October 13, giving you a growing season of approximately 178 days.

At an elevation of 1,345 feet, Iroquois County receives approximately 30 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Rue during the growing season.

Iroquois County, IL (Zone 5a) Moderate season
178 days
Last Spring Frost April 18
178 growing days
First Fall Frost October 13
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Iroquois County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (38 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 31
Recommended (50%) ✓ Fits season (38 days to spare)
Transplant: Apr 25 🍅 Harvest: Jul 4 – Sep 5
Safe Start (90%) ✓ Fits season (36 days to spare)
Transplant: May 13 🍅 Harvest: Jul 22 – Sep 23

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 Iroquois County

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

Soil pH

Your soil pH (5.9–6.7) overlaps with Rue's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Rue.

Organic Matter

Organic matter is excellent (4.5%) — Rue will thrive.

How to Plant Rue

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

Succession Planting Rue

2
successive plantings in your 178-day season

Sow every 8 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 Rue

Rue 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 Rue Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 3.6" 0" ✅ Rainfall sufficient
Jul 2.2" 3" 0" ✅ Rainfall sufficient
Aug 2.2" 2.9" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

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

Rue 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.

Rue needs ~1,100 GDD — county provides 2,447 GDD Excellent fit

Rue Planting Timeline — Iroquois County, IL

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors April 25 Apr 25 – May 9
Harvest July 4 Jul 4 – Sep 5

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
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

178 days in Iroquois County

Growing Tips for Rue in Iroquois County

Direct sow Rue outdoors after April 18 in Iroquois County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow. Plant in well-drained soil. Wear gloves when handling as sap can cause phytophotodermatitis. Prune in early spring.

Companion Planting

Good Companions

Avoid Planting Near

  • Basil
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rue in Iroquois County, IL?

Iroquois County is in Zone 5a with an average last frost of April 18. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is Iroquois County, IL?

Iroquois County, Illinois is in USDA Hardiness Zone 5a. The average last spring frost is April 18 and first fall frost is October 13.

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Your Iroquois County Garden Planner — Free

A 24-page printable planner built for Iroquois County (Zone 5a). 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 Iroquois County, IL. Local conditions may vary. Last updated: April 2026.

Sources & credits

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