When to Plant Lobelia in USDA Zone 8b
Top priorities for Zone 8b gardeners in June
June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Zone 8b.
Lobelia (Lobelia erinus) is a cool-season annual prized for the intense cobalt blue that is rare among bedding flowers. It blooms most prolifically in spring and early summer but stalls or dies back during heat peaks above 90°F. In zones 3–7 it delivers a long display; in zones 8–9 it is best treated as a spring annual that fades by midsummer. Trailing types cascade beautifully from containers and window boxes.
In Zone 8b, the average last spring frost is around February 25 and the first fall frost is around November 28, giving you a growing season of approximately 276 days.
Lobelia Planting Timeline — Zone 8b
Where Is USDA Zone 8b?
The map below highlights the states that contain Zone 8b. Click any state to see the Lobelia planting schedule for that location.
Lobelia Planting Calendar — Zone 8b
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 31 | Dec 31 – Jan 14 |
| Transplant Outdoors | January 14 | Jan 14 – Jan 28 |
| Bloom | March 11 | Mar 11 – Apr 22 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors Transplant Outdoors |
| February | — |
| March | Bloom |
| April | Bloom |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors |
Free Zone 8b Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 8b with start dates, transplant windows, and harvest times.
Growing Conditions
Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
Days to Maturity
70–80 days
Soil pH
6 – 7
Zone Temperature Range
15°F to 20°F average annual minimum
Growing Season
276 days (Zone 8b average)
Planting Specifications
| Plant Spacing | 6 inches apart |
| Row Spacing | 8 inches between rows |
Succession Planting Lobelia in Zone 8b
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Lobelia in Zone 8b
Start seeds indoors 10–12 weeks before last frost — seed is dust-fine and requires light to germinate; surface-sow and press gently. Keep at 65–70°F. Not reliably direct-sown. Transplant in cool weather, 2–4 weeks before last frost date is acceptable in zones 5+. Shear plants by one-third after the first bloom flush to encourage a second flush in fall. Provide afternoon shade in zones 7+ to extend bloom into summer.
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 Lobelia 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
Lobelia in Other Zones
Lobelia 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 Lobelia in Zone 8b?
In Zone 8b, plan your Lobelia planting around the average last frost date of February 25. Start seeds indoors around December 31. Transplant seedlings around January 14.
Can Lobelia grow in Zone 8b?
Yes, Lobelia can grow well in Zone 8b, hardy in USDA zones 3a through 9b. Zone 8b has a growing season of approximately 276 days, which is sufficient for Lobelia (70-80 days to maturity).
When can I harvest Lobelia in Zone 8b?
In Zone 8b, expect to harvest Lobelia from March 11 – April 22. Lobelia takes 70-80 days from planting to harvest.
What is the last frost date for Zone 8b?
The average last spring frost in Zone 8b is around February 25, and the first fall frost is around November 28. This gives a growing season of approximately 276 days. These are 50% probability dates — actual frost dates vary year to year.
What should I plant next to Lobelia?
Good companion plants for Lobelia include Petunias, Sweet Alyssum, Begonias, Impatiens. These companions can help with pest control, pollination, and nutrient sharing.
Your Zone 8b Garden Planner — Free
A 22-page printable planner tailored to Zone 8b. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.