Photo: Lin ScottCC BY 4.0via iNaturalistresized / cropped
Giant Lobelia Plant Care
Lobelia rhynchopetalum Hemsl.
Updated · Sources · How we source care data
With its striking bright red tubular flowers that resemble a beak, Lobelia rhynchopetalum is a native of the highlands of Kenya. This unique plant is highly sought after by collectors for its unusual flower shape and vibrant color, making it a standout addition to any garden or collection.
Every 3–7 days
Full sun to part shade
50–75°F
40–70%
At a glance
How do you care for Giant Lobelia?
Water Giant Lobelia every 3–7 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 50–75°F (10–24°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
Where Is the Giant Lobelia Native To?
What Is the Giant Lobelia?
Giant Lobelia (Lobelia rhynchopetalum) belongs to the Campanulaceae family within the Lobelia genus. Giant Lobelia is native to Ethiopia. Giant Lobelia is also known as Abyssinian Lobelia.
Giant Lobelia displays a spreading, low-growing perennial growth habit, reaching up to 0.5 ft tall with a spread of approximately 1.5 ft. Giant Lobelia produces tubular flowers in shades of blue, purple, pink, or white.
Leaf size: approximately 2 inches.
How Often Should You Water a Giant Lobelia?
Lobelia rhynchopetalum requires watering every 3–7 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 3–7 days
Let soil partially dry between waterings
What Light Does the Giant Lobelia Need?
Giant Lobelia thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Giant Lobelia Prefer?
Lobelia rhynchopetalum grows best at temperatures of 50–75°F. Giant Lobelia prefers humidity levels of 40–70%.
Temperature
50–75°F
Humidity
40–70%
What Soil Mix Works Best for a Giant Lobelia?
Moist, well-draining soil rich in organic matter. Good drainage is essential for Giant Lobelia to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Giant Lobelia?
Feed Giant Lobelia every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Giant Lobelia?
Repot every 1-2 years in spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Giant Lobelia?
Giant Lobelia can be propagated through seeds, division. Similar propagation techniques also apply to cardinal flower plant care, which shares the same genus.
Is the Giant Lobelia Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Giant Lobelia, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Giant Lobelia?
Giant Lobelia is susceptible to aphids, slugs, snails. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Giant Lobelia Need?
Giant Lobelia grows outdoors in USDA Zone 8b – 10a. It survives winters down to planting zone 8b. Giant Lobelia is native to Ethiopia.
Hardiness Zone
Zone 8b – 10a
Keep exploring plants
Giant Lobelia is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Lobelia genus — compare its care with other Lobelia species on PlantoScan.
Lobelia is part of the Campanulaceae plant family — browse all Campanulaceae genera and species.
Giant Lobelia thrives in bright light and direct sun — see other bright-light plants.
More Lobelia Species
Other Lobelia species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Lobelia rhynchopetalum Hemsl., family Campanulaceae (first published in Fl. Trop. Afr. 3: 465 (1877)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Giant Lobelia, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Photo: Lin Scott, CC BY 4.0, iNaturalist — original.
- Hardiness zone: USDA Zone 8b – 10a, estimated from the plant's typical growing conditions.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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