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When to plant Phlox in Rush County County,

Plant Phlox in Rush County County from May 1 to May 22 in spring. Rush County County sits in USDA Zone 6b, with last frost around April 24 and first frost on October 15.

When to Plant Phlox in Rush County, KS

Rush County, Kansas Zone 6b June

What to do in June

Each item below is timed to Rush County, Kansas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost April 24
Avg. first frost October 15
Soil temp (4") 74°F
Watering Moderate
Pest pressure High
Daylight 14.7 hrs
  1. Indoor seed-starting week for phlox

    You're about 17 weeks out from your last frost — the perfect window to get these germinating indoors.

July prep starts now
  • 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.

Rush County, Kansas is in USDA Zone 6b. The average last spring frost is April 24 and the first fall frost is October 15, giving you a growing season of approximately 174 days.

At an elevation of 759 feet, Rush County receives approximately 21.7 inches of rainfall annually with predominantly 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
Rush County, KS (Zone 6b) Moderate season
174 days
Last Spring Frost April 24
174 growing days
First Fall Frost October 15

Rush County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.3

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Feb 13 Transplant: Apr 24 🌸 Bloom: Jul 3 – Sep 25
Recommended (50%) ✓ Fits season (13 days to spare)
Start indoors: Feb 20 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 2
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: Mar 9 Transplant: May 18 🌸 Bloom: Jul 27 – Oct 19

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 Rush County

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

Soil pH

Your soil pH (6.4–7.3) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Phlox.

How to Plant Phlox

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

Succession Planting Phlox

2
successive plantings in your 174-day season

Sow every 9.1 weeks. Last sowing by Jun 27 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 885 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 0.5" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 4.3" 2.1" 2.2" 🚿 Regular watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 3.4" 0.9" 💧 Light watering
Jul 4.3" 2.9" 1.4" 💧 Light watering
Aug 4.3" 2.6" 1.7" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.3" 1.5" 2.8" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Rush 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 2,523 GDD Excellent fit

Phlox Planting Timeline — Rush County, KS

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors May 1 May 1 – May 15
Direct Sow May 1 May 1 – May 22
Bloom July 10 Jul 10 – Oct 2

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

Month-by-Month Timeline

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

📆 Growing Season

174 days in Rush County

Growing Tips for Phlox in Rush County

Direct sow Phlox outdoors after April 24 in Rush County when soil has warmed and frost danger has passed.

Rush County receives only 22" of rain annually. Phlox needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Rush County, KS?

Rush County is in Zone 6b with an average last frost of April 24. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rush County, KS?

Rush County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 24 and first fall frost is October 15.

When should I plant Phlox in Rush County County, ?

In Rush County County, , plant Phlox after the last frost (around April 24) and before the first frost (around October 15). Best results when soil holds above 50°F.

What growing zone is Rush County County, for Phlox?

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

Can Phlox grow in Rush County County's climate?

Yes — Phlox grows well in Rush County County's temperate climate. Rush County County averages a 174-day frost-free season, with last frost around April 24 and first frost around October 15.

🌱

Your Rush County Garden Planner — Free

A 22-page printable planner built for Rush County (Zone 6b). 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 Rush County, KS. 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.