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When to Plant Rue in San Juan County, CO

San Juan County, Colorado Zone 5a May

Your May gardening checklist

A quick May briefing for San Juan County, Colorado gardeners — what's urgent, what's next, and what can wait.

Avg. last frost June 18
Avg. first frost September 8
Soil temp (4") 32°F
Watering High
Pest pressure Low
Daylight 14 hrs
June will be here before you know it — start on
  • Transplants going out: rue

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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.

San Juan County, Colorado is in USDA Zone 5a. The average last spring frost is June 18 and the first fall frost is September 8, giving you a growing season of approximately 82 days.

At an elevation of 7,539 feet, San Juan County receives approximately 20.1 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Rue to ensure they mature before fall.

San Juan County, CO (Zone 5a) Very short season
82 days
Last Spring Frost June 18
82 growing days
First Fall Frost September 8
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San Juan County Soil Profile

Soil Type

Loam

Soil pH

6.3-8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: Jun 14 🍅 Harvest: Aug 23 – Oct 25
Recommended (50%) ✗ May not fit
Transplant: Jun 25 🍅 Harvest: Sep 3 – Nov 5
Safe Start (90%) ✗ May not fit
Transplant: Jul 6 🍅 Harvest: Sep 14 – Nov 16

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 San Juan County

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

Soil pH

Your soil pH (6.3–8.0) overlaps with Rue's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Rue.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Rue.

How to Plant Rue

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

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
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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.4" 0" ❄️ Dormant
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 2" 0.2" 💧 Light watering
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 1.6" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in San Juan 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 ~920 GDD — county provides 943 GDD Good fit

Rue Planting Timeline — San Juan County, CO

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors June 25 Jun 25 – Jul 9
Harvest September 3 Sep 3 – Nov 5

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July Transplant Outdoors
August
September Harvest
October Harvest
November Harvest
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: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

82 days in San Juan County

Growing Tips for Rue in San Juan County

Direct sow Rue outdoors after June 18 in San Juan County when soil has warmed and frost danger has passed.

Your 82.0-day growing season in San Juan County is tight for Rue (70.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

San Juan County receives only 20" 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 San Juan County, CO?

San Juan County is in Zone 5a with an average last frost of June 18. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Juan County, CO?

San Juan County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 18 and first fall frost is September 8.

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Your San Juan County Garden Planner — Free

A 24-page printable planner built for San Juan 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 San Juan County, CO. 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.