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Lobelia siphilitica
Also called Blue lobelia, Great lobelia, Blue cardinal flower
A short-lived herbaceous perennial native to eastern and central North America, grown for its blue flowers in late summer and fall. It thrives in consistently moist soil and partial shade, and is often grown in wet garden areas or at pond edges.
Lobelia siphilitica, the great blue lobelia, great lobelia, or blue cardinal flower, is a plant species within the family Campanulaceae. It is an herbaceous perennial dicot native to eastern and central Canada and United States. There are two recognized varieties of Lobelia siphilitica, var. siphilitica and var. ludoviciana. Blooming from August to October, it is short-lived, lasting only for a few years.
Although self-compatible, a flower is unable to offer pollen to itself and it must be pollinated by insects, primarily bumblebees. Bees use the lower three fused petals as a landing pad. A bee of correct weight will depress these petals on its way to the flower's nectar, this lowers the stigma wiping it against the bee's back.
Lobelia siphilitica is sold in garden centers and is often grown in zones 4 to 9. It can be propagated either by cutting or seed.
Great lobelia is found in the north from Maine to Manitoba and in the south from North Carolina to Texas. Sparse populations can be found as far west as Wyoming and Colorado.
Native Americans traditionally use Lobelia siphilitica to treat respiratory and muscle disorders. It was once considered a cure for syphilis by early European settlers, which is where the scientific name for the species originates.
Aberdare Lobelia · Lobelia alsinoides · Southern lobelia · Apache lobelia · Trailing Lobelia · Lawn Lobelia · Pale lobelia · Lobelia archeri · Lobelia arnhemiaca · Boykin's lobelia · Shortleaf lobelia · Tall Lobelia
Text excerpted from the Wikipedia article Lobelia siphilitica by its contributors, under CC BY-SA 4.0; the excerpts and the care summary drawn from them are shared under the same licence.
The care summary was written by AI (Claude, Anthropic) from the sources on this page, with general growing knowledge where they are silent. Check before relying on it.
Life form, climate and native range: World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 3.0), reformatted; see Plants of the World Online.
