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When to Plant Yarrow in San Augustine County, TX

San Augustine County, Texas Zone 9a June

June in the garden — San Augustine County, Texas

Your garden in San Augustine County, Texas is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost March 5
Avg. first frost November 16
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Start harvesting yarrow

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Coming up in July — start thinking about
  • 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.

San Augustine County, Texas is in USDA Zone 9a. The average last spring frost is March 5 and the first fall frost is November 16, giving you a growing season of approximately 256 days.

At an elevation of 146 feet, San Augustine County receives approximately 62.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 96°F, so Yarrow may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yarrow will need more frequent watering and organic matter to retain nutrients. 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
San Augustine County, TX (Zone 9a) Long season
256 days
Last Spring Frost March 5
256 growing days
First Fall Frost November 16

San Augustine County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.4-6.6

Drainage

Well Drained

Yarrow Planting Risk Windows

Early Start (70% safe) ✓ Fits season (78 days to spare)
Start indoors: Dec 31 Transplant: Feb 11 🌸 Bloom: Apr 8 – Aug 26
Recommended (50%) ✓ Fits season (74 days to spare)
Start indoors: Jan 8 Transplant: Feb 19 🌸 Bloom: Apr 16 – Sep 3
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Feb 4 Transplant: Mar 18 🌸 Bloom: May 13 – Sep 30

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 Augustine County

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

Soil pH

Your soil pH (5.4–6.6) overlaps with Yarrow's range (5.5–7.0), though not a perfect match.

Soil Texture

Sandy soil in San Augustine County warms quickly in spring but drains fast. Yarrow will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is low (1.8%). Add 2-3 inches of compost before planting Yarrow.

How to Plant Yarrow

18"
Between Plants
24"
Between Rows

Succession Planting Yarrow

5
successive plantings in your 256-day season

Sow every 6.9 weeks. Last sowing by Aug 18 to harvest before frost.

Yarrow Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/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 1.5" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 6.2" 0" ✅ Rainfall sufficient
May 2.2" 8.2" 0" ✅ Rainfall sufficient
Jun 2.2" 10.7" 0" ✅ Rainfall sufficient
Jul 2.2" 8.7" 0" ✅ Rainfall sufficient
Aug 2.2" 8.2" 0" ✅ Rainfall sufficient
Sep 2.2" 5.8" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 2.3" 0" ✅ Rainfall sufficient
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in San Augustine 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 ~1,650 GDD — county provides 5,632 GDD Excellent fit

Yarrow Planting Timeline — San Augustine County, TX

Yarrow Planting Calendar

Activity When Date Range
Start Indoors January 8 Jan 8 – Jan 22
Transplant Outdoors February 19 Feb 19 – Mar 5
Direct Sow February 19 Feb 19 – Mar 12
Bloom April 16 Apr 16 – Sep 3

· 18" apart · Rows 24" apart

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

256 days in San Augustine County

Growing Tips for Yarrow in San Augustine County

Direct sow Yarrow outdoors after March 05 in San Augustine County when soil has warmed and frost danger has passed.

Sandy soil in San Augustine County dries quickly — mulch Yarrow with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 96°F in San Augustine 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

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 San Augustine County, TX?

San Augustine County is in Zone 9a with an average last frost of March 5. Plan your Yarrow planting based on this frost date — see the calendar above for exact timing.

What planting zone is San Augustine County, TX?

San Augustine County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 5 and first fall frost is November 16.

🌱

Your San Augustine County Garden Planner — Free

A 22-page printable planner built for San Augustine County (Zone 9a). 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 San Augustine 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.