When to Plant Phlox in USDA Zone 7b
Top priorities for Zone 7b gardeners in June
Here's what deserves your attention in Zone 7b this month. Everything below is tailored to Zone 7b and timed around your local frost dates.
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Sow phlox in trays indoors
A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.
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Bring in the phlox
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
Coming up in July — start thinking about
- First harvests: phlox
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.
In Zone 7b, the average last spring frost is around March 18 and the first fall frost is around November 8, giving you a growing season of approximately 235 days.
Phlox Planting Timeline — Zone 7b
Where Is USDA Zone 7b?
The map below highlights the states that contain Zone 7b. Click any state to see the Phlox planting schedule for that location.
Phlox Planting Calendar — Zone 7b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 14 | Jan 14 – Jan 28 |
| Transplant Outdoors | March 25 | Mar 25 – Apr 8 |
| Direct Sow | March 25 | Mar 25 – Apr 15 |
| Bloom | June 3 | Jun 3 – Aug 26 |
Plant 0.3" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Bloom |
| July | Bloom |
| August | Bloom |
| September | — |
| October | — |
| November | — |
| December | — |
Free Zone 7b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 7b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
Days to Maturity
80–110 days
Soil pH
6 – 7
Zone Temperature Range
5°F to 10°F average annual minimum
Growing Season
235 days (Zone 7b average)
Planting Specifications
| Planting Depth | 0.3 inches |
| Plant Spacing | 18 inches apart |
| Row Spacing | 24 inches between rows |
Succession Planting Phlox in Zone 7b
Sow every 9.1 weeks for continuous harvest throughout the season.
Growing Tips for Phlox in Zone 7b
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
The Gardener's Encyclopedia to Companion Planting
The pairings that make vegetables, herbs, and flowers grow better — and the ones that quietly wreck a bed.
- Proven pairings for 200+ vegetables, herbs, flowers, and fruits
- Full seed-starting + planting schedule with timing and spacing
- Bonus: square-foot gardening guide + printable seasonal planners
Saving Phlox Seeds
Recommended for Your Garden
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Keep your garden organized with durable, weather-resistant plant labels.
Related Plants
Phlox in Other Zones
Phlox by State
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia
- Wisconsin
- Wyoming
Frequently Asked Questions
When should I plant Phlox in Zone 7b?
In Zone 7b, plan your Phlox planting around the average last frost date of March 18. Start seeds indoors around January 14. Direct sow outdoors around March 25. Transplant seedlings around March 25.
Can Phlox grow in Zone 7b?
Yes, Phlox can grow well in Zone 7b, hardy in USDA zones 3a through 9a. Zone 7b has a growing season of approximately 235 days, which is sufficient for Phlox (80-110 days to maturity).
When can I harvest Phlox in Zone 7b?
In Zone 7b, expect to harvest Phlox from June 3 – August 26. Phlox takes 80-110 days from planting to harvest.
What is the last frost date for Zone 7b?
The average last spring frost in Zone 7b is around March 18, and the first fall frost is around November 8. This gives a growing season of approximately 235 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Phlox?
Good companion plants for Phlox include Echinacea, Black Eyed Susan, Yarrow, Rudbeckia. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 7b Garden Planner — Free
A 22-page printable planner tailored to Zone 7b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.