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When to Plant Jostaberry in Union County, OR

Union County, Oregon Zone 6b May

Your May planting checklist for Union County, Oregon

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

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: jostaberry

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Jostaberry is a thornless hybrid of black currant and gooseberry, producing medium-sized, dark berries with a complex, tart-sweet flavor. It is vigorous and disease-resistant.

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 Jostaberry 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
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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 Jostaberry's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more acidic than Jostaberry prefers (6.0–6.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Jostaberry.

Organic Matter

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

How to Plant Jostaberry

48"
Between Plants
72"
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 Jostaberry

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

Month Jostaberry 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.

Jostaberry 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.

Jostaberry needs ~13,231 GDD — county provides 1,986 GDD May not mature

Jostaberry Planting Timeline — Union County, OR

Jostaberry Planting Calendar

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

· 48" apart · Rows 72" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

137 days in Union County

Growing Tips for Jostaberry in Union County

Direct sow Jostaberry 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 Jostaberry (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Plant in rich, well-drained soil. No special pruning required beyond removing old wood. Self-fertile but yields improve with a second bush. Berries ripen midsummer.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Jostaberry in Union County, OR?

Union County is in Zone 6b with an average last frost of May 12. Plan your Jostaberry 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.

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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.