When to plant Phlox in Marion County, MO
Plant Phlox in Marion County from April 21 to May 12 in spring. Marion County sits in USDA Zone 6a, with last frost around April 14 and first frost on October 21.
When to Plant Phlox in Marion County, MO
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.
Marion County, Missouri is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 21, giving you a growing season of approximately 190 days.
At an elevation of 1,252 feet, Marion County receives approximately 36.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Phlox to ensure they mature before fall.
Marion County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.7
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 | — | 1.5" | 0" | ❄️ Dormant |
| Feb | — | 1.5" | 0" | ❄️ Dormant |
| Mar | — | 2.7" | 0" | ❄️ Dormant |
| Apr | 4.3" | 4" | 0.3" | 💧 Light watering |
| May | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Jun | 4.3" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 3.8" | 0.5" | 💧 Light watering |
| Aug | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Sep | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Oct | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Nov | — | 2.4" | 0" | ❄️ Dormant |
| Dec | — | 2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Marion County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Phlox Planting Timeline — Marion County, MO
Phlox Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 10 | Feb 10 – Feb 24 |
| Transplant Outdoors | April 21 | Apr 21 – May 5 |
| Direct Sow | April 21 | Apr 21 – May 12 |
| Bloom | June 30 | Jun 30 – Sep 22 |
Plant 0.3" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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 | — |
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
190 days in Marion County
Growing Tips for Marion 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 →
Phlox in Other Locations
Frequently Asked Questions
When should I plant Phlox in Marion County, MO?
Marion County is in Zone 6a with an average last frost of April 14. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marion County, MO?
Marion County, Missouri is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 21.
When should I plant Phlox in Marion County, MO?
In Marion County, MO, plant Phlox after the last frost (around April 14) and before the first frost (around October 21). Best results when soil holds above 50°F.
What growing zone is Marion County, MO for Phlox?
Marion 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 Marion County's climate?
Yes — Phlox grows well in Marion County's temperate climate. Marion County averages a 190-day frost-free season, with last frost around April 14 and first frost around October 21.
Your Marion County Garden Planner — Free
A 22-page printable planner built for Marion 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.