When to Plant Hyssop in Blaine County, ID
Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.
Blaine County, Idaho is in USDA Zone 5a. The average last spring frost is May 18 and the first fall frost is October 3, giving you a growing season of approximately 138 days.
At an elevation of 7,128 feet, Blaine County receives approximately 17.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Hyssop to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Hyssop successfully. Mulch heavily to conserve soil moisture.
Blaine County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.4
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
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Hyssop Planting Timeline — Blaine County, ID
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Harvest | August 3 | Aug 3 – Oct 5 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
Sun
Full Sun (6-8+ hours)
Water
Low — drought tolerant
Days to Maturity
70–90 days
Soil pH
6 – 8
USDA Zone
Zone 5a
Growing Season
138 days
Growing Tips for Blaine County
Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Hyssop in Other Locations
Frequently Asked Questions
When should I plant Hyssop in Blaine County, ID?
Blaine County is in Zone 5a with an average last frost of May 18. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Blaine County, ID?
Blaine County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 18 and first fall frost is October 3.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Blaine County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.
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