Lobelia siphilitica

The Great Blue Lobelia is a colony-forming, clumping perennial which is well known for its long-lasting, deep violet-blue floral spires from late summer to mid-autumn. The deep blue floral racemes play exceedingly well against the dominant yellows of other fall garden greats, and draw their own share of butterflies, bees and hummingbirds. In nature, Blue Lobelia is found in wet habitats throughout eastern U.S. It bears dense spikes of intensely blue, bilaterally symmetrical flowers on the tops of sturdy, two- to three-foot stems. The florets are tubular with a two-lobed upper lip and a more prominent three-lobed lower lip. In the garden, Blue Lobelia thrives in wet to moist soil and partial sun. Full sun is tolerated if the soil is consistently moist, and it will also grow in bright shade. The soil should be fertile and loamy, acid to circumneutral pH. After seeds are produced, the flowering stem and roots die, but new offsets are formed which generate their own roots. These small offsets should be protected for the following season.