When to Plant Hyssop in Idaho 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.
Idaho County, Idaho is in USDA Zone 5a. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.
At an elevation of 6,736 feet, Idaho County receives approximately 24.5 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.
Idaho County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.8
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.
Soil Compatibility in Idaho County
How your county's soil matches Hyssop's growing requirements.
Soil pH
Your soil pH (6.3–7.8) is within Hyssop's preferred range (6.0–8.0).
Soil Texture
The loam soil in Idaho County is excellent for Hyssop — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.5%). Annual compost additions will help Hyssop.
How to Plant Hyssop
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Hyssop
Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Hyssop Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | — | 2.5" | 0" | ❄️ Dormant |
| May | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Jul | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Aug | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Oct | — | 2.3" | 0" | ❄️ Dormant |
| Nov | — | 1.7" | 0" | ❄️ Dormant |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Idaho County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Hyssop 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.
Hyssop Planting Timeline — Idaho County, ID
Hyssop Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 5 | Jun 5 – Jun 19 |
| Harvest | August 14 | Aug 14 – Oct 16 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
70–90 days
🧪 Soil pH
Needs 6–8 · Your soil: ideal
🗺️ USDA Zone
Zone 5a
📆 Growing Season
114 days in Idaho County
Growing Tips for Hyssop in Idaho County
Direct sow Hyssop outdoors after May 29 in Idaho County when soil has warmed and frost danger has passed.
Idaho County receives only 24" of rain annually. Hyssop needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Hyssop in Other Locations
Frequently Asked Questions
When should I plant Hyssop in Idaho County, ID?
Idaho County is in Zone 5a with an average last frost of May 29. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.
What planting zone is Idaho County, ID?
Idaho County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 29 and first fall frost is September 20.
Plan Your Garden with Confidence
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