When to plant Phlox in Otter Tail County, MN
Plant Phlox in Otter Tail County, between May 25 and June 15 — the only viable window. Zone 4a's short season (140 frost-free days) rules out a fall crop.
When to Plant Phlox in Otter Tail County, MN
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.
Otter Tail County, Minnesota is in USDA Zone 4a. The average last spring frost is May 11 and the first fall frost is September 28, giving you a growing season of approximately 140 days.
At an elevation of 571 feet, Otter Tail County receives approximately 40.3 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.
Otter Tail County Soil Profile
Soil Type
Silt Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Phlox Planting Timeline — Otter Tail County, MN
Phlox Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 2 | Mar 2 – Mar 16 |
| Transplant Outdoors | May 25 | May 25 – Jun 8 |
| Direct Sow | May 25 | May 25 – Jun 15 |
| Bloom | August 17 | Aug 17 – Oct 19 |
Plant 0.3" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| 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 4a
📆 Growing Season
140 days in Otter Tail County
Growing Tips for Otter Tail 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 Otter Tail County, MN?
Otter Tail County is in Zone 4a with an average last frost of May 11. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.
What planting zone is Otter Tail County, MN?
Otter Tail County, Minnesota is in USDA Hardiness Zone 4a. The average last spring frost is May 11 and first fall frost is September 28.
When should I plant Phlox in Otter Tail County, MN?
In Otter Tail County, MN, plant Phlox after the last frost (around May 11) and before the first frost (around September 28). Best results when soil holds above 50°F.
What growing zone is Otter Tail County, MN for Phlox?
Otter Tail County sits in USDA Zone 4a. Phlox grows reliably in zones 3a through 9a, so it's a good fit here.
Can Phlox grow in Otter Tail County's climate?
Yes — Phlox grows well in Otter Tail County's temperate climate. Otter Tail County averages a 140-day frost-free season, with last frost around May 11 and first frost around September 28.
Your Otter Tail County Garden Planner — Free
A 22-page printable planner built for Otter Tail County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.