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When to plant Phlox in Marshall County, KS

In Marshall County, plant Phlox in spring between April 29 and May 20, once soil temps hold above 50°F. Marshall County's last frost averages April 22, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 80–110 days before the first frost on October 14.

When to Plant Phlox in Marshall County, KS

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.

Marshall County, Kansas is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 14, giving you a growing season of approximately 175 days.

At an elevation of 840 feet, Marshall County receives approximately 22.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Phlox to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Marshall County, KS (Zone 6a) Moderate season
175 days
Last Spring Frost April 22
175 growing days
First Fall Frost October 14

Marshall County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.8

Drainage

Well Drained

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 0.6" 0" ❄️ Dormant
Feb 0.9" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 4.3" 2.2" 2.1" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 2.4" 1.9" 💧 Light watering
Sep 4.3" 2.1" 2.2" 🚿 Regular watering
Oct 4.3" 1.7" 2.6" 🚿 Regular watering
Nov 0.7" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Marshall County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Phlox Planting Timeline — Marshall County, KS

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 29 Apr 29 – May 13
Direct Sow April 29 Apr 29 – May 20
Bloom July 8 Jul 8 – Sep 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Moderate — regular watering

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: N/A

🗺️ USDA Zone

Zone 6a

📆 Growing Season

175 days in Marshall County

Growing Tips for Marshall County

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 Marshall County, KS?

Marshall County is in Zone 6a with an average last frost of April 22. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marshall County, KS?

Marshall County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 14.

When should I plant Phlox in Marshall County, KS?

In Marshall County, KS, plant Phlox after the last frost (around April 22) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Marshall County, KS for Phlox?

Marshall 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 Marshall County's climate?

Yes — Phlox grows well in Marshall County's temperate climate. Marshall County averages a 175-day frost-free season, with last frost around April 22 and first frost around October 14.

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Your Marshall County Garden Planner — Free

A 22-page printable planner built for Marshall 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 Marshall County, KS. Local conditions may vary. Last updated: August 2026.

Sources & credits

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