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When to Plant Medlar in Washington County, CO

Washington County, Colorado Zone 5b May

Washington County, Colorado gardeners: here's your May plan

May is a pivotal month for Washington County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 10
Avg. first frost October 5
Soil temp (4") 41°F
Watering High
Pest pressure Low
Daylight 14.2 hrs
  1. Move medlar from tray to bed

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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Medlar is a small ornamental tree producing unusual open-ended fruits that must be bletted (softened by frost) before eating. The flavor is complex, like spiced apple butter.

Washington County, Colorado is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 6,091 feet, Washington County receives approximately 13 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Medlar during the growing season. With low rainfall, drip irrigation is essential for growing Medlar successfully. Mulch heavily to conserve soil moisture.

Washington County, CO (Zone 5b) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5
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Washington County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 23
Recommended (50%) ✓ Fits season
Transplant: May 31
Safe Start (90%) ✓ Fits season
Transplant: Jun 10

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 Washington County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Medlar prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Medlar.

How to Plant Medlar

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.8″/week
Watering frequency 2-3 times/week
Season total 998 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Medlar

Medlar needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Medlar Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 1" 3.3" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.5" 2.8" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 4.3" 1.1" 3.2" 🚿 Regular watering
Nov 0.9" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Washington County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Medlar 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.

Medlar needs ~20,075 GDD — county provides 2,035 GDD May not mature

Medlar Planting Timeline — Washington County, CO

Medlar Planting Calendar

Activity When Date Range
Transplant Outdoors May 31 May 31 – Jun 14

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June Transplant Outdoors
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

1095–1825 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Washington County

Growing Tips for Medlar in Washington County

Direct sow Medlar outdoors after May 10 in Washington County when soil has warmed and frost danger has passed.

Your 148.0-day growing season in Washington County is tight for Medlar (1095.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.

Washington County receives only 13" of rain annually. Medlar needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant in well-drained soil. Medlars are self-fertile and need minimal pruning. Harvest after the first frost and allow to soften (blet) indoors for 2-3 weeks before eating.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Medlar in Washington County, CO?

Washington County is in Zone 5b with an average last frost of May 10. Plan your Medlar planting based on this frost date — see the calendar above for exact timing.

What planting zone is Washington County, CO?

Washington County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 5.

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Your Washington County Garden Planner — Free

A 24-page printable planner built for Washington County (Zone 5b). 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 Washington 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.