When to Plant Rosemary in Jefferson County, WA
Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.
Jefferson County, Washington is in USDA Zone 8a. The average last spring frost is April 14 and the first fall frost is October 29, giving you a growing season of approximately 198 days.
At an elevation of 205 feet, Jefferson County receives approximately 40.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Rosemary during the growing season.
Jefferson County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.8
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.
Plant Water Budget
Rosemary Planting Timeline — Jefferson County, WA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Harvest | July 14 | Jul 14 – Dec 1 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Transplant Outdoors |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | Harvest |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
80–180 days
Soil pH
6 – 7.5
USDA Zone
Zone 8a
Growing Season
198 days
Growing Tips for Jefferson County
Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.
Companion Planting
Good Companions
Level Up Your Garden
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Jefferson County, WA?
Jefferson County is in Zone 8a with an average last frost of April 14. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, WA?
Jefferson County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 14 and first fall frost is October 29.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Jefferson County gardeners in Zone 8a organize planting dates, track what's growing, and never miss a planting window.
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