When to Plant Mulberries in Walla Walla County, WA
Mulberries are fast-growing, long-lived trees that produce abundant sweet-tart berries over an extended harvest period. The berries resemble elongated blackberries.
Walla Walla County, Washington is in USDA Zone 6b. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.
At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mulberries during the growing season.
Walla Walla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
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.
Plant Water Budget
Mulberries Planting Timeline — Walla Walla County, WA
Mulberries Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 11 | May 11 – May 25 |
· 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
Moderate — regular watering
Days to Maturity
730–1825 days
Soil pH
5.5 – 7
USDA Zone
Zone 6b
Growing Season
178 days
Growing Tips for Walla Walla County
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
Level Up Your Garden
Mulberries in Other Locations
Frequently Asked Questions
When should I plant Mulberries in Walla Walla County, WA?
Walla Walla County is in Zone 6b with an average last frost of April 20. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walla Walla County, WA?
Walla Walla County, Washington is in USDA Hardiness Zone 6b. The average last spring frost is April 20 and first fall frost is October 15.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Walla Walla County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.
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