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When to Plant Rue in Harper County, OK

Harper County, Oklahoma Zone 7a May

May to-do list for Harper County, Oklahoma

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Harper County, Oklahoma.

Avg. last frost April 15
Avg. first frost October 18
Soil temp (4") 64°F
Watering Moderate
Pest pressure Low
Daylight 14 hrs

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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.

Harper County, Oklahoma is in USDA Zone 7a. The average last spring frost is April 15 and the first fall frost is October 18, giving you a growing season of approximately 186 days.

At an elevation of 861 feet, Harper County receives approximately 21.5 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Rue during the growing season.

Harper County, OK (Zone 7a) Moderate season
186 days
Last Spring Frost April 15
186 growing days
First Fall Frost October 18

Harper County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (41 days to spare)
Transplant: Apr 20 🍅 Harvest: Jun 29 – Aug 31
Recommended (50%) ✓ Fits season (46 days to spare)
Transplant: Apr 22 🍅 Harvest: Jul 1 – Sep 2
Safe Start (90%) ✓ Fits season (45 days to spare)
Transplant: May 8 🍅 Harvest: Jul 17 – Sep 18

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 Harper County

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

Soil pH

Your soil pH (6.4–7.2) is within Rue's preferred range (6.0–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.6%). Annual compost additions will help Rue.

How to Plant Rue

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

Succession Planting Rue

3
successive plantings in your 186-day season

Sow every 8 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 29 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 0.5" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 2.2" 2.2" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 3.9" 0" ✅ Rainfall sufficient
Jul 2.2" 2.9" 0" ✅ Rainfall sufficient
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 1.3" 0.9" 💧 Light watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Harper 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 ~1,340 GDD — county provides 3,115 GDD Excellent fit

Rue Planting Timeline — Harper County, OK

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors April 22 Apr 22 – May 6
Harvest July 1 Jul 1 – Sep 2

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 7a

📆 Growing Season

186 days in Harper County

Growing Tips for Rue in Harper County

Direct sow Rue outdoors after April 15 in Harper County when soil has warmed and frost danger has passed.

Harper County receives only 22" 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 Harper County, OK?

Harper County is in Zone 7a with an average last frost of April 15. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is Harper County, OK?

Harper County, Oklahoma is in USDA Hardiness Zone 7a. The average last spring frost is April 15 and first fall frost is October 18.

🌱

Your Harper County Garden Planner — Free

A 24-page printable planner built for Harper County (Zone 7a). 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 Harper County, OK. 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.