Lobelia

Lobelia is a genus of flowering plants in the family Campanulaceae, comprising about 400–450 species of annuals, perennials, and a few shrubs. Native to tropical and temperate regions of the world, with high diversity in the Americas and Africa, lobelias are valued ornamentally for their showy flowers in blue, purple, red, or white.

They are herbaceous perennials or annuals with upright to cascading stems. Leaves are alternate and simple, often with toothed margins. Flowers are tubular and bilabiate, irregular, with a two-lipped corolla that provides a landing pad for pollinators; colors range from blue and purple to red and white. Fruit is a slender capsule containing numerous tiny seeds.

Habitat and ecology: Many species prefer moist, well-drained soils and can be found in wetlands, meadows, and wood margins. Frost tolerance varies; some species are hardy in temperate gardens, others are not. Some lobelias are cultivated as ornamentals; a few species can be aggressive or invasive in suitable climates.

Uses and safety: Some species contain alkaloids such as lobeline. Historically used in traditional medicine and as an herbal remedy; Lobelia inflata was used as a smoking substitute by Indigenous peoples and in some 19th-century preparations. Modern medical use is limited and regulated due to toxicity; ingestion can cause nausea, vomiting, dizziness, seizures, or coma, and self-treatment is not recommended.

Etymology and taxonomy: The genus is named after Matthias de Lobel, a 16th-century botanist. Notable species include Lobelia cardinalis (cardinal flower), Lobelia siphilitica (great blue lobelia), and Lobelia inflata (Indian tobacco). Many cultivars are grown for their colorful flowers.