When to Plant Mulberries in Whatcom 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.
Whatcom County, Washington is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.
At an elevation of 386 feet, Whatcom County receives approximately 49 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Mulberries during the growing season.
Whatcom 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 — Whatcom County, WA
Mulberries Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 27 | Apr 27 – May 11 |
· 120" apart · Rows 144" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| 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 7b
Growing Season
206 days
Growing Tips for Whatcom 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 Whatcom County, WA?
Whatcom County is in Zone 7b with an average last frost of April 6. Plan your Mulberries planting based on this frost date — see the calendar above for exact timing.
What planting zone is Whatcom County, WA?
Whatcom County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 29.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Whatcom County gardeners in Zone 7b 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.