Lobelia siphilitica (Great Blue Lobelia)
Great Blue Lobelia, Big Blue Lobelia, Blue Cardinal Flower, Blue cardinal flower, Great Lobelia , Tall Blue Lobelia, Virginia Bellflower, Vomit RootLobelia ‘Siphilitica’, commonly referred to as Great Blue Lobelia, is a clump-forming herbaceous perennial that dazzles with its tall spikes of tubular, vibrant blue flowers. Botanically known as Lobelia siphilitica, this native North American plant flourishes in moist to wet soils, making it a perfect choice for rain gardens, pond edges, and wetlands. Its upright stems, growing up to 2–4 feet tall, are adorned with lance-shaped green leaves that provide a lush, textured backdrop to its vivid blooms. Flowering from late summer to early fall, the plant is a magnet for hummingbirds and pollinators, enhancing its ecological value.
This hardy perennial thrives in full sun to partial shade and adapts to a variety of soil conditions, though it prefers consistently moist, rich soils. Its natural tolerance for occasional flooding makes it well-suited to low-lying areas or water gardens. Largely pest-free and resistant to deer, Lobelia siphilitica is a low-maintenance yet striking addition to any garden. Its ability to self-seed ensures its presence over time while contributing to naturalized or wildlife-friendly landscapes.
Care Instructions
- Light: Performs best in full sun to partial shade.
- Soil: Prefers moist, rich, well-drained soils but adapts to wetter conditions.
- Watering: Keep soil consistently moist, especially during dry periods, to support healthy growth.
- Fertilizing: Apply a balanced fertilizer in early spring to encourage strong flowering.
- Pruning: Deadhead spent flowers to prolong blooming, and cut back stems in late fall to prepare for winter.
Lobelia ‘Siphilitica’ offers both beauty and practicality, thriving in challenging wet conditions while providing stunning color and ecological benefits. Perfect for rain gardens, bog gardens, or naturalized settings, its striking blue flowers bring seasonal vibrancy and attract valuable pollinators. Whether used as a focal point or in mass plantings, this perennial enhances outdoor spaces with both charm and function.
