When to plant Phlox in Cooper County, MO
Cooper County's climate puts the Phlox spring window between April 17 and May 8. time plantings around the expected last-frost window for best survival.
When to Plant Phlox in Cooper 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.
Cooper County, Missouri is in USDA Zone 6b. The average last spring frost is April 10 and the first fall frost is October 25, giving you a growing season of approximately 198 days.
At an elevation of 1,035 feet, Cooper County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Phlox during the growing season.
Cooper County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Phlox Planting Timeline — Cooper County, MO
Phlox Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 6 | Feb 6 – Feb 20 |
| Transplant Outdoors | April 17 | Apr 17 – May 1 |
| Direct Sow | April 17 | Apr 17 – May 8 |
| Bloom | June 26 | Jun 26 – Sep 18 |
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 6b
📆 Growing Season
198 days in Cooper County
Growing Tips for Cooper 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 Cooper County, MO?
Cooper County is in Zone 6b with an average last frost of April 10. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cooper County, MO?
Cooper County, Missouri is in USDA Hardiness Zone 6b. The average last spring frost is April 10 and first fall frost is October 25.
When should I plant Phlox in Cooper County, MO?
In Cooper County, MO, plant Phlox after the last frost (around April 10) and before the first frost (around October 25). Best results when soil holds above 50°F.
What growing zone is Cooper County, MO for Phlox?
Cooper 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 Cooper County's climate?
Yes — Phlox grows well in Cooper County's temperate climate. Cooper County averages a 198-day frost-free season, with last frost around April 10 and first frost around October 25.
Your Cooper County Garden Planner — Free
A 22-page printable planner built for Cooper 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.