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When to Plant Rue in Union County, IA

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.

Union County, Iowa is in USDA Zone 5a. The average last spring frost is April 23 and the first fall frost is October 11, giving you a growing season of approximately 171 days.

At an elevation of 1,311 feet, Union County receives approximately 39 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83ยฐF, so choose short-season varieties of Rue to ensure they mature before fall.

Union County, IA (Zone 5a) Moderate season
171 days
Last Spring Frost April 23
171 growing days
First Fall Frost October 11

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Transplant: Apr 24 🍅 Harvest: Jul 3 – Sep 4
Recommended (50%) ✓ Fits season (31 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 10
Safe Start (90%) ✓ Fits season (28 days to spare)
Transplant: May 16 🍅 Harvest: Jul 25 – Sep 26

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.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Rue needs ~980 GDD — county provides 2,094 GDD Excellent fit

Rue Planting Timeline โ€” Union County, IA

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors April 30 Apr 30 โ€“ May 14
Harvest July 9 Jul 9 โ€“ Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Low โ€” drought tolerant

Days to Maturity

70โ€“90 days

Soil pH

6 โ€“ 7.5

USDA Zone

Zone 5a

Growing Season

171 days

Growing Tips for Union County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Rue in Union County, IA?

Union County is in Zone 5a with an average last frost of April 23. Plan your Rue planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Union County, IA?

Union County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 23 and first fall frost is October 11.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Union County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

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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 Union County, IA. Local conditions may vary. Last updated: April 2026.