Lobelia siphilitica (Great Blue Lobelia)

Lobelia siphilitica, commonly known as Great Blue Lobelia, is a hardy, clump-forming perennial with tall spikes of showy, tubular, bright blue to violet flowers. The blooms rise above a base of lance-shaped, toothed green leaves, creating a striking vertical accent in the garden. This native North American wildflower is an excellent choice for moist borders, naturalized plantings, or pollinator gardens, as it attracts bees, butterflies, and hummingbirds.

Lobelia siphilitica thrives in consistently moist, well-drained soils and is ideal for areas near ponds, streams, or in rain gardens. It tolerates wet conditions and is also moderately drought-tolerant once established. This low-maintenance perennial is deer- and rabbit-resistant, making it a reliable choice for wildlife-friendly gardens. It pairs beautifully with other moisture-loving perennials like asters, rudbeckia, and sedges. Deadheading spent blooms encourages prolonged flowering, and allowing some flowers to go to seed can promote natural self-seeding for future seasons.

Sun Requirements:

Full Sun. Prefers full sun in cooler climates but benefits from partial shade in hotter regions to prevent leaf scorch.

Maximum Growth Height:

24–36 inches (60–90 cm), with a spread of about 12–18 inches (30–45 cm).

Bloom Month:

August to October. Blooms in late summer through early fall, adding vibrant color to the garden as the season transitions.