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When to Plant Rue in Allegheny County, PA

Allegheny County, Pennsylvania Zone 6b May

What to do in May

A quick May briefing for Allegheny County, Pennsylvania gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 25
Avg. first frost October 28
Soil temp (4") 62°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
  1. Set out rue seedlings

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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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.

Allegheny County, Pennsylvania is in USDA Zone 6b. The average last spring frost is April 25 and the first fall frost is October 28, giving you a growing season of approximately 186 days.

At an elevation of 118 feet, Allegheny County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Rue during the growing season.

Allegheny County, PA (Zone 6b) Moderate season
186 days
Last Spring Frost April 25
186 growing days
First Fall Frost October 28

Allegheny County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (42 days to spare)
Transplant: Apr 26 🍅 Harvest: Jul 5 – Sep 6
Recommended (50%) ✓ Fits season (46 days to spare)
Transplant: May 2 🍅 Harvest: Jul 11 – Sep 12
Safe Start (90%) ✓ Fits season (37 days to spare)
Transplant: May 21 🍅 Harvest: Jul 30 – Oct 1

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 Allegheny County

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

Soil pH

Your soil pH (5.0–6.5) is more acidic than Rue prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.8%). 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 30 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 3" 0" ❄️ Dormant
Feb 3.1" 0" ❄️ Dormant
Mar 3.7" 0" ❄️ Dormant
Apr 2.2" 3.2" 0" ✅ Rainfall sufficient
May 2.2" 3.4" 0" ✅ Rainfall sufficient
Jun 2.2" 3.5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Allegheny 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 — Allegheny County, PA

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors May 2 May 2 – May 16
Harvest July 11 Jul 11 – Sep 12

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

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: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

186 days in Allegheny County

Growing Tips for Rue in Allegheny County

Direct sow Rue outdoors after April 25 in Allegheny 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 Allegheny County, PA?

Allegheny County is in Zone 6b with an average last frost of April 25. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is Allegheny County, PA?

Allegheny County, Pennsylvania is in USDA Hardiness Zone 6b. The average last spring frost is April 25 and first fall frost is October 28.

🌱

Your Allegheny County Garden Planner — Free

A 24-page printable planner built for Allegheny County (Zone 6b). 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 Allegheny County, PA. 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.