When to Plant Boysenberries in Umatilla County, OR
Boysenberries are a cross between raspberries, blackberries, and loganberries, producing large, dark, intensely flavored berries. They are excellent for jams and pies.
Umatilla County, Oregon is in USDA Zone 6a. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.
At an elevation of 2,195 feet, Umatilla County receives approximately 14.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Boysenberries during the growing season. With low rainfall, drip irrigation is essential for growing Boysenberries successfully. Mulch heavily to conserve soil moisture.
Umatilla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.8
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 Umatilla County
How your county's soil matches Boysenberries's growing requirements.
Soil pH
Your soil pH (5.2–6.8) overlaps with Boysenberries's range (5.5–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Umatilla County is excellent for Boysenberries — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Boysenberries will thrive.
How to Plant Boysenberries
Plant Water Budget
Monthly Watering Guide for Boysenberries
Boysenberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Boysenberries Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| May | 4.3" | 0.9" | 3.4" | 🚿 Regular watering |
| Jun | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Jul | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Aug | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Sep | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Oct | 4.3" | 1.4" | 2.9" | 🚿 Regular watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Umatilla County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Boysenberries 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.
Boysenberries Planting Timeline — Umatilla County, OR
Boysenberries Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 14 | May 14 – May 28 |
· 24" apart · Rows 72" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
365–730 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 6a
📆 Growing Season
180 days in Umatilla County
Growing Tips for Boysenberries in Umatilla County
Direct sow Boysenberries outdoors after April 23 in Umatilla County when soil has warmed and frost danger has passed.
Your 180.0-day growing season in Umatilla County is tight for Boysenberries (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.
Umatilla County receives only 15" of rain annually. Boysenberries needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Provide strong trellising for vigorous canes. Prune spent canes to ground after harvest. Mulch heavily to retain moisture. Protect from wind to prevent cane damage.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Boysenberries in Other Locations
Frequently Asked Questions
When should I plant Boysenberries in Umatilla County, OR?
Umatilla County is in Zone 6a with an average last frost of April 23. Plan your Boysenberries planting based on this frost date — see the calendar above for exact timing.
What planting zone is Umatilla County, OR?
Umatilla County, Oregon is in USDA Hardiness Zone 6a. The average last spring frost is April 23 and first fall frost is October 20.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Umatilla County gardeners in Zone 6a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.