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When to plant Phlox in Dunklin County, MO

Plant Phlox in Dunklin County from April 3 to April 24 in spring. Dunklin County sits in USDA Zone 7b, with last frost around March 27 and first frost on November 2.

When to Plant Phlox in Dunklin County, MO

Dunklin County, Missouri Zone 7b July

Top priorities for Dunklin County, Missouri gardeners in July

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Dunklin County, Missouri.

Avg. last frost March 27
Avg. first frost November 2
Soil temp (4") 85°F
Watering Moderate
Pest pressure High
Daylight 14.2 hrs
  1. Start harvesting phlox

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

Coming up in August — start thinking about
  • 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.

Dunklin County, Missouri is in USDA Zone 7b. The average last spring frost is March 27 and the first fall frost is November 2, giving you a growing season of approximately 220 days.

At an elevation of 1,344 feet, Dunklin County receives approximately 33.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 94°F, providing good warmth for Phlox during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Dunklin County, MO (Zone 7b) Long season
220 days
Last Spring Frost March 27
220 growing days
First Fall Frost November 2

Dunklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-7.1

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (62 days to spare)
Start indoors: Jan 15 Transplant: Mar 26 🌸 Bloom: Jun 4 – Aug 27
Recommended (50%) ✓ Fits season (59 days to spare)
Start indoors: Jan 23 Transplant: Apr 3 🌸 Bloom: Jun 12 – Sep 4
Safe Start (90%) ✓ Fits season (59 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🌸 Bloom: Jul 2 – Sep 24

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 Dunklin County

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

Soil pH

Your soil pH (5.6–7.1) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). 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 220-day season

Sow every 9.1 weeks. Last sowing by Jul 15 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 706 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 1.4" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 4.3" 2.4" 1.9" 💧 Light watering
Apr 4.3" 2.8" 1.5" 💧 Light watering
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.8" 1.5" 💧 Light watering
Nov 4.3" 2.4" 1.9" 💧 Light watering
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Dunklin 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 ~1,948 GDD — county provides 4,510 GDD Excellent fit

Phlox Planting Timeline — Dunklin County, MO

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors April 3 Apr 3 – Apr 17
Direct Sow April 3 Apr 3 – Apr 24
Bloom June 12 Jun 12 – Sep 4

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

220 days in Dunklin County

Growing Tips for Phlox in Dunklin County

Direct sow Phlox outdoors after March 27 in Dunklin 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 Dunklin County, MO?

Dunklin County is in Zone 7b with an average last frost of March 27. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Dunklin County, MO?

Dunklin County, Missouri is in USDA Hardiness Zone 7b. The average last spring frost is March 27 and first fall frost is November 2.

When should I plant Phlox in Dunklin County, MO?

In Dunklin County, MO, plant Phlox after the last frost (around March 27) and before the first frost (around November 2). Best results when soil holds above 50°F.

What growing zone is Dunklin County, MO for Phlox?

Dunklin County sits in USDA Zone 7b. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.

Can Phlox grow in Dunklin County's climate?

Yes — Phlox grows well in Dunklin County's temperate climate. Dunklin County averages a 220-day frost-free season, with last frost around March 27 and first frost around November 2.

🌱

Your Dunklin County Garden Planner — Free

A 22-page printable planner built for Dunklin County (Zone 7b). 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 Dunklin County, MO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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