Lobelia
flower
Cool-season annual — performs best in spring and fall. May slow in summer heat but rebounds when temperatures drop. Excellent edging plant. Keep consistently moist.
At a glance
- USDA Zones
- 3–10
- Sun
- Part sun (3–6 hrs)
- Water
- Medium — water when top inch of soil is dry
- Soil
- Loam
- pH
- Neutral, acidic
- Spacing
- 6 in. between plants
- Per square foot
- 4 plants per square
Planting & harvest windows
Northern Hemisphere timing. Adjust ±4–6 weeks based on your last/first frost dates.
| Activity | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Plant | ||||||||||||
| Harvest |
Plant Harvest
Good companions
Recommended varieties
- Crystal Palaceboth
Deep blue compact mounds — the classic edging lobelia.
- Sapphireboth
Trailing type with blue flowers and white eye — great for bed edges.
- Rosamundboth
Carmine red with white eye — adds warm color contrast.
Add Lobelia to your raised bed — the planner handles spacing and companion warnings automatically.
Open the planner →