André Karwath aka Aka / CC BY-SA 2.5
garden
Lobelia
Lobelia
MedicinalToxic — Use Caution
Overview
A genus with both ornamental garden annuals and potent medicinal native perennials. The delicate trailing lobelias in blue and white are garden favorites for containers and edges, while the native great blue lobelia and cardinal flower are striking wetland wildflowers. Lobelia inflata (Indian tobacco) has a significant but complex medicinal history as a respiratory herb.
Growing Conditions
LightPartial Sun
MoistureWet
Hardiness Zones3 — 7
Height1m
Spread0.3m
Growth HabitForb/herb
Pollinator Valuehigh
Companion Planting & Soil
Good Companions
Soil pH5.5 — 7
Soil TypeRich, moist, well-drained soil; some species prefer wet conditions
Planting Calendar
When to sow, transplant, and harvest by growing zone.
| Zone | Action | Months | Notes |
|---|---|---|---|
| Cold (1-2) | Start Indoors | Feb — Mar | Start indoors 10-12 weeks early; dust-like seeds need light; very slow |
| Cold (1-2) | Transplant | Jun — Jun | Transplant after frost; trailing types superb in hanging baskets |
| Cold (1-2) | Bloom | Jun — Aug | Bloom until heat shuts it down; shear back and water — may rebloom in cool fall |
| Cool (3-4) | Start Indoors | Jan — Feb | Start indoors 12 weeks early; do not cover seeds |
| Cool (3-4) | Transplant | May — May | Transplant after last frost; part shade in warm areas |
| Cool (3-4) | Bloom | May — Jul | Spring/summer bloom; brilliant blue cascade |
| Moderate (5-7) | Transplant | Mar — Apr | Transplant in spring; electric blue flowers; cool-season performer |
| Moderate (5-7) | Bloom | Apr — Jun | Spring bloom; fades above 80°F; shear for possible fall comeback |
| Warm (8-9) | Transplant | Sep — Oct | Fall plant for cool-season bloom; dies in summer heat |
| Warm (8-9) | Bloom | Oct — Apr (wraps) | Fall through spring bloom |
| Hot (10+) | Transplant | Oct — Nov | Fall/winter plant; cool season only |
| Hot (10+) | Bloom | Nov — Mar (wraps) | Winter bloom; heat kills it |
Uses
Medicinal
- L. inflata historically used as a respiratory antispasmodic (professional use only)
- Traditional smoking cessation aid (lobeline is similar to nicotine)
- External use for muscle spasms and pain
Other Uses
- Trailing varieties excellent for containers and hanging baskets
- Native species for rain gardens and wetland edges
Safety Notes
The plant is potentially toxic, but the degree of toxicity is unknown[222]. It contains the alkaloid lobeline which has a similar effect upon the nervous system as nicotine[274]. he sap of the plant has been known to cause skin irritation[274].
