When to Plant Aronia in Union County, OR
Your May planting checklist for Union County, Oregon
Welcome to May in Zone 6b. These are the moves that will have the biggest impact on your growing season.
June prep starts now
- Transplants going out: aronia
Aronia (chokeberry) is an extremely hardy native shrub producing astringent dark berries rich in antioxidants. The berries are typically processed into juice, jam, or wine.
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 Aronia during the growing season.
Union County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.6
Drainage
Well Drained
Plant Planting Risk Windows
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 Aronia's growing requirements.
Soil pH
Your soil pH (5.2–6.6) is within Aronia's preferred range (5.0–7.0).
Soil Texture
The silt loam soil in Union County is excellent for Aronia — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Aronia.
Organic Matter
Organic matter is excellent (5.6%) — Aronia will thrive.
How to Plant Aronia
Plant Water Budget
Monthly Watering Guide for Aronia
Aronia needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Aronia 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.
Aronia 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.
Aronia Planting Timeline — Union County, OR
Aronia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 2 | Jun 2 – Jun 16 |
· 48" apart · Rows 72" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
730–1095 days
🧪 Soil pH
Needs 5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
137 days in Union County
Growing Tips for Aronia in Union County
Direct sow Aronia 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 Aronia (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.
Union County receives only 24" of rain annually. Aronia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Plant in full sun for best fruiting. Very adaptable to soil types. Minimal pest and disease problems. Harvest berries in fall when fully black. Suckers can be divided for propagation.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Aronia in Other Locations
Frequently Asked Questions
When should I plant Aronia in Union County, OR?
Union County is in Zone 6b with an average last frost of May 12. Plan your Aronia 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.