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When to Plant Persimmon in Union County, OR

Union County, Oregon Zone 6b May

Top priorities for Union County, Oregon gardeners in May

Each item below is timed to Union County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 12
Avg. first frost September 26
Soil temp (4") 53°F
Watering High
Pest pressure Low
Daylight 14.7 hrs
To set up a strong June, finish these tasks
  • Transplants going out: persimmon

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Persimmons are ornamental trees producing sweet, honey-flavored fruits in fall. American persimmons are astringent until fully ripe while Asian types can be eaten firm.

Union County, Oregon is in USDA Zone 6b. The average last spring frost is May 12 and the first fall frost is September 26, giving you a growing season of approximately 137 days.

At an elevation of 2,751 feet, Union County receives approximately 23.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Persimmon during the growing season.

Union County, OR (Zone 6b) Short season
137 days
Last Spring Frost May 12
137 growing days
First Fall Frost September 26

Union County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 24
Recommended (50%) ✓ Fits season
Transplant: Jun 2
Safe Start (90%) ✓ Fits season
Transplant: Jun 29

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 Persimmon's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more acidic than Persimmon prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Persimmon.

Organic Matter

Organic matter is excellent (5.6%) — Persimmon will thrive.

How to Plant Persimmon

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 707 gal / 100 sq ft

Monthly Watering Guide for Persimmon

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

Month Persimmon Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.4" 3.9" 🚿 Regular watering
Aug 4.3" 0.5" 3.8" 🚿 Regular watering
Sep 4.3" 1" 3.3" 🚿 Regular watering
Oct 2" 0" ❄️ Dormant
Nov 3.8" 0" ❄️ Dormant
Dec 4.2" 0" ❄️ Dormant

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

Persimmon 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.

Persimmon needs ~26,462 GDD — county provides 1,986 GDD May not mature

Persimmon Planting Timeline — Union County, OR

Persimmon Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 – Jun 16

· 120" apart · Rows 144" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

1095–2555 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Union County

Growing Tips for Persimmon in Union County

Direct sow Persimmon outdoors after May 12 in Union County when soil has warmed and frost danger has passed.

Your 137.0-day growing season in Union County is tight for Persimmon (1095.0-2555.0 days to maturity). Start indoors and choose early-maturing varieties.

Union County receives only 24" of rain annually. Persimmon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Choose self-fertile varieties or plant male and female trees. American types must be fully soft-ripe before eating. Asian varieties may be eaten when firm. Minimal pruning needed.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Persimmon in Union County, OR?

Union County is in Zone 6b with an average last frost of May 12. Plan your Persimmon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, OR?

Union County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 12 and first fall frost is September 26.

🌱

Your Union County Garden Planner — Free

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