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When to Plant Rue in Clark County, WI

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.

Clark County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 13 and the first fall frost is September 30, giving you a growing season of approximately 140 days.

At an elevation of 850 feet, Clark County receives approximately 39.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 82ยฐF, so choose short-season varieties of Rue to ensure they mature before fall.

Clark County, WI (Zone 4a) Short season
140 days
Last Spring Frost May 13
140 growing days
First Fall Frost September 30

Clark County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (5 days to spare)
Transplant: May 12 🍅 Harvest: Jul 21 – Sep 22
Recommended (50%) ✓ Fits season (0 days to spare)
Transplant: May 20 🍅 Harvest: Jul 29 – Sep 30
Safe Start (90%) ✓ Fits season (6 days to spare)
Transplant: May 28 🍅 Harvest: Aug 6 – Oct 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 Clark County

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

Soil pH

Your soil pH (6.1โ€“6.8) is within Rue's preferred range (6.0โ€“7.5).

Soil Texture

The silt loam soil in Clark County is excellent for Rue โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.9%). Annual compost additions will help Rue.

How to Plant Rue

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

Succession Planting Rue

2
successive plantings in your 140-day season

Sow every 8 weeks. Last sowing by Jul 02 to harvest before frost.

Plant Water Budget

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

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 โ€” 1.8" 0" โ„๏ธ Dormant
Feb โ€” 2" 0" โ„๏ธ Dormant
Mar โ€” 2.6" 0" โ„๏ธ Dormant
Apr โ€” 3.9" 0" โ„๏ธ Dormant
May 2.2" 4.6" 0" โœ… Rainfall sufficient
Jun 2.2" 4.6" 0" โœ… Rainfall sufficient
Jul 2.2" 4.2" 0" โœ… Rainfall sufficient
Aug 2.2" 4.2" 0" โœ… Rainfall sufficient
Sep 2.2" 3.7" 0" โœ… Rainfall sufficient
Oct โ€” 2.8" 0" โ„๏ธ Dormant
Nov โ€” 3" 0" โ„๏ธ Dormant
Dec โ€” 2.4" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Clark County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~920 GDD — county provides 1,610 GDD Excellent fit

Rue Planting Timeline โ€” Clark County, WI

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors May 20 May 20 โ€“ Jun 3
Harvest July 29 Jul 29 โ€“ Sep 30

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Full Sun (6-8+ hours)

๐Ÿ’ง Water

0.5"/week ยท Natural rainfall sufficient

๐Ÿ“… Days to Maturity

70โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: ideal

๐Ÿ—บ๏ธ USDA Zone

Zone 4a

๐Ÿ“† Growing Season

140 days in Clark County

Growing Tips for Rue in Clark County

Direct sow Rue outdoors after May 13 in Clark 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 Clark County, WI?

Clark County is in Zone 4a with an average last frost of May 13. Plan your Rue planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Clark County, WI?

Clark County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 13 and first fall frost is September 30.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Clark County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Clark County, WI. Local conditions may vary. Last updated: April 2026.