Description
Blue Lobelia (Lobelia siphilitica), also called Great Blue Lobelia, is a showy native perennial with rich blue to violet flower spikes that bloom from mid-summer into early fall. Growing about 2–3 feet tall, it adds strong vertical color right when many landscapes shift to yellows.
The tubular flowers attract bees, butterflies, and hummingbirds. The plant contains a compound called lobeline, which helps deter deer and other herbivores. It is a short-lived perennial, typically lasting a few years, but it will self-seed and form small colonies over time.
Blue Lobelia grows best in full sun to partial shade and prefers medium to wet soils. It’s commonly found in wet prairies, meadows, pond edges, and low areas, making it a strong choice for rain gardens and naturalized plantings.
It pairs especially well with Cardinal Flower (Lobelia cardinalis), which blooms around the same time with vivid red flowers, creating a strong color contrast. Together, they provide excellent late-season nectar for hummingbirds and add bold interest to moist plantings.
