When to plant Tarragon in Flathead County, MT
Plant Tarragon in Flathead County, between June 10 and June 24 — the only viable window. Zone 5a's short season (99 frost-free days) rules out a fall crop.
When to Plant Tarragon in Flathead County, MT
June in Flathead County, Montana — your action list
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Flathead County, Montana.
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Time to transplant tarragon
Frost risk is low now in Flathead County, Montana. If you've been covering beds overnight, you can stop.
French tarragon is a perennial herb with slender leaves and a distinctive anise-like flavor essential in French cooking. It does not produce viable seed and must be propagated vegetatively.
Flathead County, Montana is in USDA Zone 5a. The average last spring frost is June 3 and the first fall frost is September 10, giving you a growing season of approximately 99 days.
At an elevation of 6,233 feet, Flathead County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Tarragon during the growing season.
Flathead County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.4
Drainage
Well Drained
Tarragon 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 Flathead County
How your county's soil matches Tarragon's growing requirements.
Soil pH
Your soil pH (6.6–8.4) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Flathead County is excellent for Tarragon — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Tarragon.
How to Plant Tarragon
Tarragon Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Tarragon
Tarragon needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.
| Month | Tarragon Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | — | 2.7" | 0" | ❄️ Dormant |
| Jun | 1.7" | 1.5" | 0.2" | 💧 Light watering |
| Jul | 1.7" | 1.5" | 0.2" | 💧 Light watering |
| Aug | 1.7" | 2.1" | 0" | ✅ Rainfall sufficient |
| Sep | 1.7" | 1.5" | 0.2" | 💧 Light watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.6" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Flathead County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Tarragon 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.
Tarragon Planting Timeline — Flathead County, MT
Tarragon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | June 10 | Jun 10 – Jun 24 |
| Harvest | August 12 | Aug 12 – Oct 21 |
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
0.4"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
99 days in Flathead County
Growing Tips for Tarragon in Flathead County
Direct sow Tarragon outdoors after June 03 in Flathead County when soil has warmed and frost danger has passed.
Your 99.0-day growing season in Flathead County is tight for Tarragon (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Tarragon in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Purchase plants or divisions as French tarragon does not grow true from seed. Plant in well-drained soil. Divide every 3-4 years to maintain vigor. Harvest tips regularly for best flavor.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Tarragon in Other Locations
Frequently Asked Questions
When should I plant Tarragon in Flathead County, MT?
Flathead County is in Zone 5a with an average last frost of June 3. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Flathead County, MT?
Flathead County, Montana is in USDA Hardiness Zone 5a. The average last spring frost is June 3 and first fall frost is September 10.
When should I plant Tarragon in Flathead County, MT?
In Flathead County, MT, plant Tarragon after the last frost (around June 3) and before the first frost (around September 10). Best results when soil holds above 50°F.
What growing zone is Flathead County, MT for Tarragon?
Flathead County sits in USDA Zone 5a. Tarragon grows reliably in zones 4a through 9b, so it's a good fit here.
Can Tarragon grow in Flathead County's climate?
Yes — Tarragon grows well in Flathead County's temperate climate. Flathead County averages a 99-day frost-free season, with last frost around June 3 and first frost around September 10.
Your Flathead County Garden Planner — Free
A 22-page printable planner built for Flathead County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.