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When to plant Phlox in Suwannee County, FL

The best window to plant Phlox in Suwannee County, is February 18–March 11, when soil warms to 50°F. Last frost typically hits March 4; first frost November 26.

When to Plant Phlox in Suwannee County, FL

Suwannee County, Florida Zone 9a July

July in Suwannee County, Florida — your action list

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

Avg. last frost March 4
Avg. first frost November 26
Soil temp (4") 91°F
Watering Low
Pest pressure High
Daylight 13.8 hrs

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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.

Suwannee County, Florida is in USDA Zone 9a. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.

At an elevation of 383 feet, Suwannee County receives approximately 53.6 inches of rainfall annually with predominantly sand soil. Summer highs average 91°F, providing good warmth for Phlox during the growing season. Sandy soil warms quickly in spring — great for early planting — but Phlox will need more frequent watering and organic matter to retain nutrients. 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
Suwannee County, FL (Zone 9a) Long season
267 days
Last Spring Frost March 4
267 growing days
First Fall Frost November 26

Suwannee County Soil Profile

Soil Type

Sand

Soil pH

5.1-6

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Dec 25 Transplant: Feb 5 🌸 Bloom: Apr 16 – Jun 11
Recommended (50%) ✓ Fits season (155 days to spare)
Start indoors: Jan 7 Transplant: Feb 18 🌸 Bloom: Apr 29 – Jun 24
Safe Start (90%) ✓ Fits season (159 days to spare)
Start indoors: Jan 27 Transplant: Mar 10 🌸 Bloom: May 19 – Jul 14

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 Suwannee County

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

Soil pH

Your soil pH (5.1–6.0) is more acidic than Phlox prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is low (1.4%). 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 267-day season

Sow every 9.1 weeks. Last sowing by Aug 08 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 373 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 2.5" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 4.3" 3.2" 1.1" 💧 Light watering
Apr 4.3" 2.6" 1.7" 💧 Light watering
May 4.3" 3.8" 0.5" 💧 Light watering
Jun 4.3" 8" 0" ✅ Rainfall sufficient
Jul 4.3" 7.8" 0" ✅ Rainfall sufficient
Aug 4.3" 7.3" 0" ✅ Rainfall sufficient
Sep 4.3" 7.1" 0" ✅ Rainfall sufficient
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Suwannee 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 ~1,734 GDD — county provides 4,872 GDD Excellent fit

Phlox Planting Timeline — Suwannee County, FL

Phlox Planting Calendar

Activity When Date Range
Start Indoors January 7 Jan 7 – Jan 21
Transplant Outdoors February 18 Feb 18 – Mar 4
Direct Sow February 18 Feb 18 – Mar 11
Bloom April 29 Apr 29 – Jun 24

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_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

267 days in Suwannee County

Growing Tips for Phlox in Suwannee County

Direct sow Phlox outdoors after March 04 in Suwannee County when soil has warmed and frost danger has passed.

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

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 Suwannee County, FL?

Suwannee County is in Zone 9a with an average last frost of March 4. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Suwannee County, FL?

Suwannee County, Florida is in USDA Hardiness Zone 9a. The average last spring frost is March 4 and first fall frost is November 26.

When should I plant Phlox in Suwannee County, FL?

In Suwannee County, FL, plant Phlox after the last frost (around March 4) and before the first frost (around November 26). Best results when soil holds above 50°F.

What growing zone is Suwannee County, FL for Phlox?

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

Can Phlox grow in Suwannee County's climate?

Yes — Phlox grows well in Suwannee County's temperate climate. Suwannee County averages a 267-day frost-free season, with last frost around March 4 and first frost around November 26.

🌱

Your Suwannee County Garden Planner — Free

A 22-page printable planner built for Suwannee 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 Suwannee County, FL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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