When to Plant Rosemary in Blanco County, TX
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.
Blanco County, Texas is in USDA Zone 8a. The average last spring frost is March 8 and the first fall frost is November 21, giving you a growing season of approximately 258 days.
At an elevation of 4,826 feet, Blanco County receives approximately 61.5 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Rosemary during the growing season. Clay soil retains moisture well for Rosemary, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rosemary root diseases.
Blanco County Soil Profile
Soil Type
Clay
Soil pH
7.1-7.7
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 Blanco County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (7.1–7.7) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
Your clay soil in Blanco County is workable for Rosemary. Add compost annually to improve structure.
Organic Matter
Organic matter is moderate (3.1%). Annual compost additions will help Rosemary.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by May 25 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Rosemary
Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.
| Month | Rosemary Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.8" | 0" | ❄️ Dormant |
| Mar | 1.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Apr | 1.3" | 5.8" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 10.3" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 7.7" | 0" | ✅ Rainfall sufficient |
| Aug | 1.3" | 6.7" | 0" | ✅ Rainfall sufficient |
| Sep | 1.3" | 6.4" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | 1.3" | 2" | 0" | ✅ Rainfall sufficient |
| Dec | — | 1.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Blanco County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Rosemary 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.
Rosemary Planting Timeline — Blanco County, TX
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | March 15 | Mar 15 – Mar 29 |
| Harvest | June 7 | Jun 7 – Oct 25 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Transplant Outdoors |
| April | — |
| May | — |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
80–180 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 8a
📆 Growing Season
258 days in Blanco County
Growing Tips for Rosemary in Blanco County
Direct sow Rosemary outdoors after March 08 in Blanco County when soil has warmed and frost danger has passed.
With Blanco County's clay soil (36% clay), work in 3-4 inches of compost before planting Rosemary. Avoid tilling when soil is wet to prevent compaction.
With 62" of annual rainfall in Blanco County, ensure good drainage for Rosemary — excess moisture can promote root rot and fungal diseases.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Blanco County, TX?
Blanco County is in Zone 8a with an average last frost of March 8. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Blanco County, TX?
Blanco County, Texas is in USDA Hardiness Zone 8a. The average last spring frost is March 8 and first fall frost is November 21.
Plan Your Garden with Confidence
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