Lobelia siphilitica

The Lobelia siphilitaca or Syphilitic Lobelia is a charming perennial that thrives in moist to wet soil and deserves to be used more often in gardens. It has upright stems with large leaves at their base and large floral spikes, from early summer to early autumn, composed of blue flowers tinged with mauve. It prefers sunny, non-scorching exposures, but also not too dense shade. A perfect plant for flowering in your woodland areas or pond edges.

The Syphilitic Lobelia is a tall, erect perennial native to North America. It has a fast growth rate and can reach 60 to 90 cm (24 to 35in) in height with a spread of 30 cm (12in) per stem. Its leaves are dark green and lanceolate, alternating along the stem. They start off large at the base of the stem and become progressively smaller towards the floral spike, similar to foxglove leaves. From August to October, floral spikes at the top of the stems reveal flowers that progressively open along the spikes. Its beautiful blue flowers tinged with mauve have a trumpet shape, similar to Snapdragons (Antirrhinum majus), ending with two cut, outward-curved lips. This perennial tends to have a short lifespan, but self-seeds under favorable conditions without becoming invasive. Its above-ground, deciduous vegetation dries up in autumn and regrows in spring.

The Syphilitic Lobelia is highly frost hardy (-20° C). Allow for a relatively large space for the plant to develop and charm you with its vigor. It thrives in heavy, ordinary, moist to wet soils and can tolerate short periods of root submersion. It enjoys sunny exposures with moist soil, but also shaded exposures in a consistently moist summer soil. It is ideal for water gardens, pond edge plantings, and woodland areas. Its striking habit is complemented by Phlox, Grasses, Goat's Beards, and Astilbes.