When to Plant Lobelia in USDA Zone 9a
Zone 9a gardeners: here's your June plan
Your Zone 9a garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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 9a, the average last spring frost is around February 10 and the first fall frost is around December 10, giving you a growing season of approximately 303 days.
Lobelia Planting Timeline — Zone 9a
Where Is USDA Zone 9a?
The map below highlights the states that contain Zone 9a. Click any state to see the Lobelia planting schedule for that location.
Lobelia Planting Calendar — Zone 9a
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | December 16 | Dec 16 – Dec 30 |
| Transplant Outdoors | December 16 | Dec 16 – Dec 30 |
| Bloom | February 10 | Feb 10 – Mar 10 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Bloom |
| March | Bloom |
| April | — |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | Start Indoors Transplant Outdoors |
Free Zone 9a Planting Calendar PDF
Know exactly when to plant every crop in your zone. Get a printable month-by-month calendar customized for Zone 9a 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
20°F to 25°F average annual minimum
Growing Season
303 days (Zone 9a average)
Planting Specifications
| Plant Spacing | 6 inches apart |
| Row Spacing | 8 inches between rows |
Succession Planting Lobelia in Zone 9a
Sow every 8 weeks for continuous harvest throughout the season.
Growing Tips for Lobelia in Zone 9a
Zone 9a offers a long growing season (~303 days). You can plant Lobelia earlier and may get multiple harvests.
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
Reduce heat stress and sun scorch in hot climates with UV-stabilized shade cloth.
Start seeds indoors with reusable cell trays and humidity domes.
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
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 9a?
In Zone 9a, plan your Lobelia planting around the average last frost date of February 10. Start seeds indoors around December 16. Transplant seedlings around December 16.
Can Lobelia grow in Zone 9a?
Yes, Lobelia can grow well in Zone 9a, hardy in USDA zones 3a through 9b. Zone 9a has a growing season of approximately 303 days, which is sufficient for Lobelia (70-80 days to maturity).
When can I harvest Lobelia in Zone 9a?
In Zone 9a, expect to harvest Lobelia from February 10 – March 10. Lobelia takes 70-80 days from planting to harvest.
What is the last frost date for Zone 9a?
The average last spring frost in Zone 9a is around February 10, and the first fall frost is around December 10. This gives a growing season of approximately 303 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 9a Garden Planner — Free
A 22-page printable planner tailored to Zone 9a. Planting dates, monthly task lists, harvest log, seed inventory, and succession charts — everything you need to plan a full season.