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When to plant Phlox in Scott County, MN

In Zone 4b (Scott County), direct-sow Phlox between May 8 and May 29 for spring, after the April 24 last-frost mark.

When to Plant Phlox in Scott County, MN

Scott County, Minnesota Zone 4b July

Your July gardening checklist

Your Scott County, Minnesota garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.

Avg. last frost April 24
Avg. first frost October 9
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 15.1 hrs
  1. Time to start phlox inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Basket week: phlox

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

To set up a strong August, finish these tasks
  • 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.

Scott County, Minnesota is in USDA Zone 4b. The average last spring frost is April 24 and the first fall frost is October 9, giving you a growing season of approximately 168 days.

At an elevation of 1,105 feet, Scott County receives approximately 39.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Phlox to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly Good for cutting Fragrant
Scott County, MN (Zone 4b) Moderate season
168 days
Last Spring Frost April 24
168 growing days
First Fall Frost October 9

Scott County Soil Profile

Soil Type

Silt Loam

Soil pH

5.9-7

Drainage

Well Drained

Phlox Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Feb 6 Transplant: May 1 🌸 Bloom: Jul 24 – Oct 2
Recommended (50%) ✓ Fits season (0 days to spare)
Start indoors: Feb 13 Transplant: May 8 🌸 Bloom: Jul 31 – Oct 9
Safe Start (90%) ✗ May not fit
Start indoors: Mar 4 Transplant: May 27 🌸 Bloom: Aug 19 – Oct 28

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 Scott County

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

Soil pH

Your soil pH (5.9–7.0) overlaps with Phlox's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — 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 168-day season

Sow every 9.1 weeks. Last sowing by Jun 21 to harvest before frost.

Phlox Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 7 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 1.6" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 4.5" 0" ✅ Rainfall sufficient
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 3.1" 1.2" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Scott 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 ~950 GDD — county provides 1,680 GDD Excellent fit

Phlox Planting Timeline — Scott County, MN

Phlox Planting Calendar

Activity When Date Range
Start Indoors February 13 Feb 13 – Feb 27
Transplant Outdoors May 8 May 8 – May 22
Direct Sow May 8 May 8 – May 29
Bloom July 31 Jul 31 – Oct 9

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March
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 · Only during dry spells

📅 Days to Maturity

80–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4b

📆 Growing Season

168 days in Scott County

Growing Tips for Phlox in Scott County

Direct sow Phlox outdoors after April 24 in Scott 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 Scott County, MN?

Scott County is in Zone 4b 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 Scott County, MN?

Scott County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 24 and first fall frost is October 9.

When should I plant Phlox in Scott County, MN?

In Scott County, MN, plant Phlox after the last frost (around April 24) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Scott County, MN for Phlox?

Scott County sits in USDA Zone 4b. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.

Can Phlox grow in Scott County's climate?

Yes — Phlox grows well in Scott County's temperate climate. Scott County averages a 168-day frost-free season, with last frost around April 24 and first frost around October 9.

🌱

Your Scott County Garden Planner — Free

A 22-page printable planner built for Scott County (Zone 4b). 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 Scott County, MN. Local conditions may vary. Last updated: July 2026.

Sources & credits

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