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When to Plant Phlox in Kendall County, TX

Kendall County, Texas Zone 8b June

Kendall County, Texas gardeners: here's your June plan

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Kendall County, Texas.

Avg. last frost March 9
Avg. first frost November 20
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Collect phlox at their peak

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

To set up a strong July, finish these tasks
  • First harvests: phlox

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Garden Phlox (Phlox paniculata) is a beloved native perennial of eastern North America, producing large, domed clusters of fragrant flowers atop upright stems from mid-summer into fall. Its sweet honey-like fragrance carries on summer evenings and draws hummingbirds, butterflies, and sphinx moths. Modern cultivars offer colors spanning white, pink, salmon, red, purple, and bicolors. A classic cottage garden stalwart, phlox combines well with black-eyed Susans, echinacea, and ornamental grasses in naturalistic plantings. Select mildew-resistant cultivars for best long-term performance.

Kendall County, Texas is in USDA Zone 8b. The average last spring frost is March 9 and the first fall frost is November 20, giving you a growing season of approximately 256 days.

At an elevation of 2,187 feet, Kendall County receives approximately 54.6 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Phlox may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Phlox root diseases.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Kendall County, TX (Zone 8b) Long season
256 days
Last Spring Frost March 9
256 growing days
First Fall Frost November 20
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Kendall County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.4

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Start indoors: Jan 3 Transplant: Feb 28 🌸 Bloom: May 9 – Jul 18
Recommended (50%) ✓ Fits season (116 days to spare)
Start indoors: Jan 12 Transplant: Mar 9 🌸 Bloom: May 18 – Jul 27
Safe Start (90%) ✓ Fits season (108 days to spare)
Start indoors: Feb 10 Transplant: Apr 7 🌸 Bloom: Jun 16 – Aug 25

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 Kendall County

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

Soil pH

Your soil pH (6.4–7.4) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Phlox.

How to Plant Phlox

0.3"
Planting Depth
18"
Between Plants
24"
Between Rows

Succession Planting Phlox

3
successive plantings in your 256-day season

Sow every 9.1 weeks. Last sowing by Aug 02 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 237 gal / 100 sq ft

Monthly Watering Guide for Phlox

Phlox needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Phlox Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 2.2" 0" ❄️ Dormant
Mar 4.3" 3.3" 1" 💧 Light watering
Apr 4.3" 6.5" 0" ✅ Rainfall sufficient
May 4.3" 7.6" 0" ✅ Rainfall sufficient
Jun 4.3" 8.2" 0" ✅ Rainfall sufficient
Jul 4.3" 6.9" 0" ✅ Rainfall sufficient
Aug 4.3" 6.3" 0" ✅ Rainfall sufficient
Sep 4.3" 5.4" 0" ✅ Rainfall sufficient
Oct 4.3" 3.4" 0.9" 💧 Light watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Kendall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Phlox 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.

Phlox needs ~2,019 GDD — county provides 5,440 GDD Excellent fit

Phlox Planting Timeline — Kendall County, TX

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors March 9 Mar 9 – Mar 23
Direct Sow March 9 Mar 9 – Mar 30
Bloom May 18 May 18 – Jul 27

Plant 0.3" deep · 18" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

256 days in Kendall County

Growing Tips for Phlox in Kendall County

Direct sow Phlox outdoors after March 09 in Kendall County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors 8–10 weeks before last frost, or transplant container divisions in spring. Named cultivar seeds may not come true; divisions from named plants are the preferred propagation method. Space generously (18–24 inches) and avoid overhead watering to reduce powdery mildew risk. Good air circulation is critical — thin clumps to the strongest 5–7 stems per plant in spring. Deadhead after the primary bloom flush to encourage secondary flowering. Division every 2–3 years in spring keeps plants vigorous. Fall planting of divisions (Zones 5+) is equally effective. Year 2+ plants develop into full clumps with the most prolific bloom.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Phlox in Kendall County, TX?

Kendall County is in Zone 8b with an average last frost of March 9. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kendall County, TX?

Kendall County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 9 and first fall frost is November 20.

🌱

Your Kendall County Garden Planner — Free

A 22-page printable planner built for Kendall County (Zone 8b). 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 Kendall 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.