Blog

When to Plant Phlox in Medina County, TX

Medina County, Texas Zone 9a June

June in Medina County, Texas — your action list

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

Avg. last frost March 3
Avg. first frost November 23
Soil temp (4") 80°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Harvest phlox as they ripen

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

Instant PDF download. No spam, unsubscribe any time.

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.

Medina County, Texas is in USDA Zone 9a. The average last spring frost is March 3 and the first fall frost is November 23, giving you a growing season of approximately 265 days.

At an elevation of 1,498 feet, Medina County receives approximately 56.7 inches of rainfall annually with predominantly loam soil. Summer highs average 92°F, providing good warmth for Phlox during the growing season. 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
Medina County, TX (Zone 9a) Long season
265 days
Last Spring Frost March 3
265 growing days
First Fall Frost November 23

Medina County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Dec 23 Transplant: Feb 3 🌸 Bloom: Apr 14 – Jun 9
Recommended (50%) ✓ Fits season (153 days to spare)
Start indoors: Jan 6 Transplant: Feb 17 🌸 Bloom: Apr 28 – Jun 23
Safe Start (90%) ✓ Fits season (142 days to spare)
Start indoors: Feb 4 Transplant: Mar 18 🌸 Bloom: May 27 – Jul 22

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 Medina County

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

Soil pH

Your soil pH (6.6–7.6) is more alkaline than Phlox prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Phlox.

How to Plant Phlox

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

Succession Planting Phlox

3
successive plantings in your 265-day season

Sow every 9.1 weeks. Last sowing by Aug 05 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 287 gal / 100 sq ft
Drought risk

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

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 1.9" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 5.6" 0" ✅ Rainfall sufficient
May 4.3" 8.1" 0" ✅ Rainfall sufficient
Jun 4.3" 8" 0" ✅ Rainfall sufficient
Jul 4.3" 8.3" 0" ✅ Rainfall sufficient
Aug 4.3" 6.8" 0" ✅ Rainfall sufficient
Sep 4.3" 5.6" 0" ✅ Rainfall sufficient
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Medina 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 ~1,805 GDD — county provides 5,035 GDD Excellent fit

Phlox Planting Timeline — Medina County, TX

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 6 Jan 6 – Jan 20
Transplant Outdoors February 17 Feb 17 – Mar 3
Direct Sow February 17 Feb 17 – Mar 10
Bloom April 28 Apr 28 – Jun 23

Plant 0.3" deep · 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
August
September
October
November
December

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: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

265 days in Medina County

Growing Tips for Phlox in Medina County

Direct sow Phlox outdoors after March 03 in Medina 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 Medina County, TX?

Medina County is in Zone 9a with an average last frost of March 3. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Medina County, TX?

Medina County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 3 and first fall frost is November 23.

🌱

Your Medina County Garden Planner — Free

A 22-page printable planner built for Medina 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Medina 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.