Edging lobelia Lobelia erinus
Edging lobelia (Lobelia erinus) is an annual flowering plant in the Campanulaceae family, native to South Africa. It grows 10–25 cm (4–10 in) tall and 15–30 cm (6–12 in) wide, wants part sun to part shade and moderate water, and is hardy to about 0 °C (32 °F). Space plants about 15 cm (6 in) apart.
Plan Edging lobelia in your garden →
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Edging lobelia at a glance
| Type | Annual flowering plant |
|---|---|
| Family | Campanulaceae |
| Mature height | 10–25 cm (4–10 in) |
| Mature spread | 15–30 cm (6–12 in) |
| Spacing | 15 cm (6 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Moderate; drought tolerance none, waterlogging tolerance low |
| Soil pH | 5.5–7 |
| Cold hardiness | About 0 °C (32 °F) once established (roughly USDA zone 10) |
| Heat stress | Likely above about 26 °C (79 °F) |
| Flowering | about 5–10 weeks after planting, for 13–17 weeks |
| Days to maturity | About 80 days from planting |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | South Africa |
| Common in gardens of | 🇬🇧 United Kingdom, 🇿🇦 South Africa, 🇺🇸 United States |
Is Edging lobelia toxic?
- People: mildly toxic
- Cats: not well documented
- Dogs: not well documented
- Parts: all parts
Lobelia species contain lobeline-type alkaloids; Lobelia erinus is considered low in toxicity but is not well documented.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Edging lobelia
No well-documented helpful pairing. Group it with plants that like part sun to part shade and moderate water.
Questions about Edging lobelia
- How far apart should I plant Edging lobelia?
- About 15 cm (6 in) apart, centre to centre. A mature plant spreads 15–30 cm (6–12 in).
- Does Edging lobelia need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Edging lobelia need?
- Moderate water. Drought tolerance is none and waterlogging tolerance low.
- How cold-hardy is Edging lobelia?
- It tolerates about 0 °C (32 °F) once established, roughly USDA zone 10. As an annual it is usually planted out after the last frost.
- When does Edging lobelia flower?
- About 5–10 weeks after planting, for 13–17 weeks.
- Is Edging lobelia poisonous to cats and dogs?
- For cats it is not well documented; for dogs not well documented; for people mildly toxic. Lobelia species contain lobeline-type alkaloids; Lobelia erinus is considered low in toxicity but is not well documented.
- What grows well with Edging lobelia?
- There is no well-documented companion pairing for Edging lobelia. Group it with plants that like the same sun (part sun to part shade) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- RHS Plant Finder, Royal Horticultural Society
- PlantZAfrica, South African National Biodiversity Institute
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Tender perennial grown as an annual; sulks and stops flowering in midsummer heat unless sheared and kept moist.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Canterbury bells Campanula medium
- Balloon flower Platycodon grandiflorus
- Fairy's thimble Campanula cochleariifolia
- Deodeok (bonnet bellflower) Codonopsis lanceolata
- Cardinal flower Lobelia cardinalis
- Great blue lobelia Lobelia siphilitica
- Dwarf grassy bells (edraianthus) Edraianthus pumilio
- Dalmatian bellflower (wall bellflower) Campanula portenschlagiana