When to plant Phlox in Robertson County, KY
Aim to plant Phlox in Robertson County on or after April 23; the window stays open through May 14. Robertson County's 193-day frost-free season gives you enough for a full main crop and a short fall succession.
When to Plant Phlox in Robertson County, KY
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.
Robertson County, Kentucky is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 26, giving you a growing season of approximately 193 days.
At an elevation of 2,352 feet, Robertson County receives approximately 43 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Phlox during the growing season.
Robertson County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.5
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 | — | 3.9" | 0" | ❄️ Dormant |
| Feb | — | 3.3" | 0" | ❄️ Dormant |
| Mar | — | 4.2" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 4.3" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 4.4" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| Nov | — | 3.1" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Robertson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Phlox Planting Timeline — Robertson County, KY
Phlox Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 12 | Feb 12 – Feb 26 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 23 | Apr 23 – May 14 |
| Bloom | July 2 | Jul 2 – Sep 24 |
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 | — |
| 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
193 days in Robertson County
Growing Tips for Robertson 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 Robertson County, KY?
Robertson County is in Zone 6b with an average last frost of April 16. Plan your Phlox planting based on this frost date — see the calendar above for exact timing.
What planting zone is Robertson County, KY?
Robertson County, Kentucky is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 26.
When should I plant Phlox in Robertson County, KY?
In Robertson County, KY, plant Phlox after the last frost (around April 16) and before the first frost (around October 26). Best results when soil holds above 50°F.
What growing zone is Robertson County, KY for Phlox?
Robertson 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 Robertson County's climate?
Yes — Phlox grows well in Robertson County's temperate climate. Robertson County averages a 193-day frost-free season, with last frost around April 16 and first frost around October 26.
Your Robertson County Garden Planner — Free
A 22-page printable planner built for Robertson 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.