When to Plant Yarrow in San Patricio County, TX
Your May game plan for San Patricio County, Texas
Here's what deserves your attention in San Patricio County, Texas this month. Everything below is tailored to Zone 9b and timed around your local frost dates.
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It's harvest week for yarrow
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Get ahead of June
- First harvests: yarrow
Yarrow is a drought-tolerant perennial herb with feathery foliage and flat-topped flower clusters in white, yellow, pink, or red. It attracts beneficial insects and is used in herbal medicine.
San Patricio County, Texas is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 9, giving you a growing season of approximately 300 days.
At an elevation of 2,449 feet, San Patricio County receives approximately 54.7 inches of rainfall annually with predominantly loam soil. Summer highs average 100°F, so Yarrow may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yarrow root diseases.
San Patricio County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.2
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 San Patricio County
How your county's soil matches Yarrow's growing requirements.
Soil pH
Your soil pH (6.8–7.2) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.
Soil Texture
The loam soil in San Patricio County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is low (1.9%). Add 2-3 inches of compost before planting Yarrow.
How to Plant Yarrow
Plant Water Budget
Monthly Watering Guide for Yarrow
Yarrow 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 | Yarrow Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.5" | 0" | ❄️ Dormant |
| Feb | 2.2" | 1.7" | 0.5" | 💧 Light watering |
| Mar | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.4" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 8.5" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 8.1" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 7.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 5" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.1" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2" | 0.2" | 💧 Light watering |
| Dec | 2.2" | 1.4" | 0.8" | 💧 Light watering |
Water needs are for active growing months only (Feb–Dec in San Patricio County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Yarrow 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.
Yarrow Planting Timeline — San Patricio County, TX
Yarrow Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 19 | Feb 19 – Mar 5 |
| Harvest | May 21 | May 21 – Aug 6 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Transplant Outdoors |
| March | Transplant Outdoors |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
90–120 days
🧪 Soil pH
Needs 5.5–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 9b
📆 Growing Season
300 days in San Patricio County
Growing Tips for Yarrow in San Patricio County
Direct sow Yarrow outdoors after February 12 in San Patricio County when soil has warmed and frost danger has passed.
With summer highs reaching 100°F in San Patricio County, provide afternoon shade for Yarrow and water deeply in the morning.
Common pests for Yarrow in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow or start from divisions. Yarrow thrives in poor soil and is very drought-tolerant. Deadhead to encourage reblooming. Divide clumps every 3 years.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Yarrow in Other Locations
Frequently Asked Questions
When should I plant Yarrow in San Patricio County, TX?
San Patricio County is in Zone 9b with an average last frost of February 12. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Patricio County, TX?
San Patricio County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 12 and first fall frost is December 9.
Your San Patricio County Garden Planner — Free
A 24-page printable planner built for San Patricio County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.