When to Plant Mulberries in Multnomah County, OR
Mulberries are fast-growing, long-lived trees that produce abundant sweet-tart berries over an extended harvest period. The berries resemble elongated blackberries.
Multnomah County, Oregon is in USDA Zone 8b. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.
At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Mulberries to ensure they mature before fall.
Multnomah County Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.3
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 Multnomah County
How your county's soil matches Mulberries's growing requirements.
Soil pH
Your soil pH (5.8–6.3) is within Mulberries's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in Multnomah County is excellent for Mulberries — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Mulberries.
Organic Matter
Organic matter is excellent (4.5%) — Mulberries will thrive.
How to Plant Mulberries
Plant Water Budget
Monthly Watering Guide for Mulberries
Mulberries needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Mulberries Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.8" | 0" | ❄️ Dormant |
| Feb | — | 4.1" | 0" | ❄️ Dormant |
| Mar | — | 3.5" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.3" | 2" | 💧 Light watering |
| May | 4.3" | 2.3" | 2" | 💧 Light watering |
| Jun | 4.3" | 1.3" | 3" | 🚿 Regular watering |
| Jul | 4.3" | 0.6" | 3.7" | 🚿 Regular watering |
| Aug | 4.3" | 0.7" | 3.6" | 🚿 Regular watering |
| Sep | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Oct | 4.3" | 2.9" | 1.4" | 💧 Light watering |
| Nov | — | 6" | 0" | ❄️ Dormant |
| Dec | — | 4.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Multnomah County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mulberries 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.
Mulberries Planting Timeline — Multnomah County, OR
Mulberries Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 5 | May 5 – May 19 |
· 120" apart · Rows 144" 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
730–1825 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 8b
📆 Growing Season
196 days in Multnomah County
Growing Tips for Mulberries in Multnomah County
Direct sow Mulberries outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.
Your 196.0-day growing season in Multnomah County is tight for Mulberries (730.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Plant away from driveways and patios as fallen berries stain. Minimal pruning is needed. Harvest by shaking branches over a tarp. Birds love mulberries so plant extra.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Mulberries in Other Locations
Frequently Asked Questions
When should I plant Mulberries in Multnomah County, OR?
Multnomah County is in Zone 8b with an average last frost of April 14. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.
What planting zone is Multnomah County, OR?
Multnomah County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 14 and first fall frost is October 27.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Multnomah County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.
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