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When to plant Phlox in Macon County County,

For Macon County County, gardeners: plant Phlox April 20 through May 11 once soil reads 50°F.

When to Plant Phlox in Macon County, IL

Macon County, Illinois Zone 6a June

June to-do list for Macon County, Illinois

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

Avg. last frost April 13
Avg. first frost October 19
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Indoor seed-starting week for phlox

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Collect phlox at their peak

    If you can't use it all right away, check the food-preservation section of your planner.

A few tasks this June that'll pay off in July
  • 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.

Macon County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 19, giving you a growing season of approximately 189 days.

At an elevation of 1,064 feet, Macon County receives approximately 31.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Phlox during the growing season.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Macon County, IL (Zone 6a) Moderate season
189 days
Last Spring Frost April 13
189 growing days
First Fall Frost October 19
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Macon County Soil Profile

Soil Type

Silt Loam

Soil pH

6-7.1

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (28 days to spare)
Start indoors: Feb 3 Transplant: Apr 14 🌸 Bloom: Jun 23 – Sep 15
Recommended (50%) ✓ Fits season (28 days to spare)
Start indoors: Feb 9 Transplant: Apr 20 🌸 Bloom: Jun 29 – Sep 21
Safe Start (90%) ✓ Fits season (31 days to spare)
Start indoors: Feb 20 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 2

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 Macon County

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

Soil pH

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

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — Phlox will thrive.

How to Plant Phlox

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

Succession Planting Phlox

2
successive plantings in your 189-day season

Sow every 9.1 weeks. Last sowing by Jul 01 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 512 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 1.3" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 3.5" 0.8" 💧 Light watering
Aug 4.3" 3.5" 0.8" 💧 Light watering
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Macon 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 ~1,378 GDD — county provides 2,740 GDD Excellent fit

Phlox Planting Timeline — Macon County, IL

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 9 Feb 9 – Feb 23
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow April 20 Apr 20 – May 11
Bloom June 29 Jun 29 – Sep 21

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
July Bloom
August Bloom
September Bloom
October
November
December
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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 6a

📆 Growing Season

189 days in Macon County

Growing Tips for Phlox in Macon County

Direct sow Phlox outdoors after April 13 in Macon 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 Macon County, IL?

Macon County is in Zone 6a with an average last frost of April 13. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Macon County, IL?

Macon County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 19.

When should I plant Phlox in Macon County County, ?

In Macon County County, , plant Phlox after the last frost (around April 13) and before the first frost (around October 19). Best results when soil holds above 50°F.

What growing zone is Macon County County, for Phlox?

Macon County County sits in USDA Zone 6a. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.

Can Phlox grow in Macon County County's climate?

Yes — Phlox grows well in Macon County County's temperate climate. Macon County County averages a 189-day frost-free season, with last frost around April 13 and first frost around October 19.

🌱

Your Macon County Garden Planner — Free

A 22-page printable planner built for Macon County (Zone 6a). 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 Macon County, IL. 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.