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When to Plant Yarrow in Webb County, TX

Webb County, Texas Zone 9b June

Your June planting checklist for Webb County, Texas

Welcome to June in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 9
Avg. first frost December 9
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.7 hrs
  1. Pick yarrow

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

Get ahead of July
  • First harvests: yarrow

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Achillea millefolium (Yarrow) is a tough, drought-tolerant native perennial with aromatic finely-divided foliage and broad flat-topped flower clusters that serve as a landing platform for hundreds of beneficial insect species. Available in white (the species type) and a wide range of cultivars spanning yellow, gold, pink, salmon, and deep red. Spreads by rhizome to form ground-covering colonies; blooms from late spring through midsummer with reblooming into fall if deadheaded. Exceptional in hot, dry sites where other perennials fail.

Webb County, Texas is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 9, giving you a growing season of approximately 303 days.

At an elevation of 3,543 feet, Webb County receives approximately 50.9 inches of rainfall annually with predominantly loam soil. Summer highs average 95°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.

Perennial Blooms in Summer Pollinator-friendly Deer-resistant Good for cutting Fragrant
Webb County, TX (Zone 9b) Year-round
303 days
Last Spring Frost February 9
303 growing days
First Fall Frost December 9

Webb County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Yarrow Planting Risk Windows

Early Start (70% safe) ✓ Fits season (149 days to spare)
Start indoors: Nov 24 Transplant: Jan 5 🌸 Bloom: Mar 2 – Jul 6
Recommended (50%) ✓ Fits season (135 days to spare)
Start indoors: Dec 15 Transplant: Jan 26 🌸 Bloom: Mar 23 – Jul 27
Safe Start (90%) ✓ Fits season (123 days to spare)
Start indoors: Jan 8 Transplant: Feb 19 🌸 Bloom: Apr 16 – Aug 20

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 Webb County

How your county's soil matches Yarrow's growing requirements.

Soil pH

Your soil pH (6.6–7.7) is more alkaline than Yarrow prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Webb County is excellent for Yarrow — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Yarrow.

How to Plant Yarrow

18"
Between Plants
24"
Between Rows

Succession Planting Yarrow

6
successive plantings in your 303-day season

Sow every 6.9 weeks. Last sowing by Sep 10 to harvest before frost.

Yarrow Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.3" 0" ❄️ Dormant
Feb 2.2" 1.9" 0.3" 💧 Light watering
Mar 2.2" 2.8" 0" ✅ Rainfall sufficient
Apr 2.2" 5" 0" ✅ Rainfall sufficient
May 2.2" 8.3" 0" ✅ Rainfall sufficient
Jun 2.2" 7.6" 0" ✅ Rainfall sufficient
Jul 2.2" 5.9" 0" ✅ Rainfall sufficient
Aug 2.2" 6.4" 0" ✅ Rainfall sufficient
Sep 2.2" 5.2" 0" ✅ Rainfall sufficient
Oct 2.2" 3.4" 0" ✅ Rainfall sufficient
Nov 2.2" 1.7" 0.5" 💧 Light watering
Dec 2.2" 1.5" 0.7" 💧 Light watering

Water needs are for active growing months only (Feb–Dec in Webb 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 needs ~1,594 GDD — county provides 6,460 GDD Excellent fit

Yarrow Planting Timeline — Webb County, TX

Yarrow Planting Calendar

Activity When Date Range
Start Indoors December 15 Dec 15 – Dec 29
Transplant Outdoors January 26 Jan 26 – Feb 9
Direct Sow January 19 Jan 19 – Feb 9
Bloom March 23 Mar 23 – Jul 27

· 18" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January Transplant Outdoors Direct Sow
February Transplant Outdoors Direct Sow
March Bloom
April Bloom
May Bloom
June Bloom
July Bloom
August
September
October
November
December Start Indoors

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

303 days in Webb County

Growing Tips for Yarrow in Webb County

Direct sow Yarrow outdoors after February 09 in Webb County when soil has warmed and frost danger has passed.

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

Start seeds indoors 8–10 weeks before last frost; seeds need light for germination — press onto soil surface, do not cover. Direct sow after last frost or divide established clumps in spring or fall. Thrives in poor, well-drained soil — rich soil and high fertility cause floppy stems and reduce flower count. Avoid overwatering; excellent drought tolerance once established. Deadhead spent clusters to encourage rebloom. Divide every 2–3 years to prevent center die-out and control spread. Year 2+ plants bloom most heavily; first-year plants may produce limited flowers. Dried flowers retain color well for arrangements.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yarrow in Webb County, TX?

Webb County is in Zone 9b with an average last frost of February 9. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is Webb County, TX?

Webb County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 9.

🌱

Your Webb County Garden Planner — Free

A 22-page printable planner built for Webb 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Webb County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.