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When to Plant Rue in Union County, SD

Union County, South Dakota Zone 5a May

May in the garden — Union County, South Dakota

Your garden in Union County, South Dakota is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 30
Avg. first frost October 5
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.5 hrs
  1. Plant out rue

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

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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.

Union County, South Dakota is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 5, giving you a growing season of approximately 158 days.

At an elevation of 938 feet, Union County receives approximately 22.8 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Rue during the growing season.

Union County, SD (Zone 5a) Moderate season
158 days
Last Spring Frost April 30
158 growing days
First Fall Frost October 5
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Union County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (20 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 10
Recommended (50%) ✓ Fits season (18 days to spare)
Transplant: May 7 🍅 Harvest: Jul 16 – Sep 17
Safe Start (90%) ✓ Fits season (13 days to spare)
Transplant: May 22 🍅 Harvest: Jul 31 – Oct 2

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 Union County

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

Soil pH

Your soil pH (6.8–7.2) is within Rue's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). 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 158-day season

Sow every 8 weeks. Last sowing by Jul 07 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 0.7" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.2" 2.8" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.1" 0" ✅ Rainfall sufficient
Aug 2.2" 2.4" 0" ✅ Rainfall sufficient
Sep 2.2" 1.9" 0.3" 💧 Light watering
Oct 2.2" 1.5" 0.7" 💧 Light watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Union 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 ~1,160 GDD — county provides 2,291 GDD Excellent fit

Rue Planting Timeline — Union County, SD

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors May 7 May 7 – May 21
Harvest July 16 Jul 16 – Sep 17

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
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: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

158 days in Union County

Growing Tips for Rue in Union County

Direct sow Rue outdoors after April 30 in Union County when soil has warmed and frost danger has passed.

Union County receives only 23" of rain annually. Rue needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Union County, SD?

Union County is in Zone 5a with an average last frost of April 30. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, SD?

Union County, South Dakota is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 5.

🌱

Your Union County Garden Planner — Free

A 24-page printable planner built for Union 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 Union County, SD. 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.