When to Plant Tarragon in Williamson County, TX
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.
Williamson County, Texas is in USDA Zone 8b. The average last spring frost is March 5 and the first fall frost is November 22, giving you a growing season of approximately 262 days.
At an elevation of 1,023 feet, Williamson County receives approximately 53.3 inches of rainfall annually with predominantly clay soil. Summer highs average 94°F, providing good warmth for Tarragon during the growing season. Clay soil retains moisture well for Tarragon, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tarragon root diseases.
Williamson County Soil Profile
Soil Type
Clay
Soil pH
7.1-7.8
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 Williamson County
How your county's soil matches Tarragon's growing requirements.
Soil pH
Your soil pH (7.1–7.8) overlaps with Tarragon's range (6.0–7.5), though not a perfect match.
Soil Texture
Heavy clay soil (46% clay) in Williamson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Drainage
Drainage is adequate for Tarragon.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Tarragon.
How to Plant Tarragon
Succession Planting Tarragon
Sow every 6.9 weeks. Last sowing by Aug 24 to harvest before frost.
Plant Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 2" | 0" | ❄️ Dormant |
| Mar | 1.7" | 3.4" | 0" | ✅ Rainfall sufficient |
| Apr | 1.7" | 6.5" | 0" | ✅ Rainfall sufficient |
| May | 1.7" | 7.7" | 0" | ✅ Rainfall sufficient |
| Jun | 1.7" | 7.6" | 0" | ✅ Rainfall sufficient |
| Jul | 1.7" | 6.6" | 0" | ✅ Rainfall sufficient |
| Aug | 1.7" | 6.1" | 0" | ✅ Rainfall sufficient |
| Sep | 1.7" | 5.4" | 0" | ✅ Rainfall sufficient |
| Oct | 1.7" | 3.7" | 0" | ✅ Rainfall sufficient |
| Nov | 1.7" | 1.7" | 0" | ✅ Rainfall sufficient |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Williamson 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 — Williamson County, TX
Tarragon Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 12 | Mar 12 – Mar 26 |
| Harvest | May 14 | May 14 – Jul 23 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | — |
| September | — |
| October | — |
| 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 8b
📆 Growing Season
262 days in Williamson County
Growing Tips for Tarragon in Williamson County
Direct sow Tarragon outdoors after March 05 in Williamson County when soil has warmed and frost danger has passed.
With Williamson County's clay soil (46% clay), work in 3-4 inches of compost before planting Tarragon. Avoid tilling when soil is wet to prevent compaction.
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 Williamson County, TX?
Williamson County is in Zone 8b with an average last frost of March 5. Plan your Tarragon planting based on this frost date — see the calendar above for exact timing.
What planting zone is Williamson County, TX?
Williamson County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 5 and first fall frost is November 22.
Plan Your Garden with Confidence
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