Lobelia siphilitica, Great Blue Lobelia, is the blue brother of remarkably red cardinal flower, L. cardinalis. They are both part of the very garden-worthy bellflower family, Campanulaceae. In the wild, where it is thrilling to come upon, Great Blue Lobelia is most often seen in part sun to part shade, near streams, sloughs, and other wetlands, telling you that in the garden it prefers moist soil. Where content, it attains a height of two to three feet and colonizes through self-seeding. In most gardens, it persists for years. The summer flowers of Great Blue Lobelia are various shades of violet-blue, lipped, lobed, and arranged on a long stalk. They are an important food source for several native bees, bumblebees, and hummingbirds. Photo by Mary Free, Master Gardeners of Northern Virginia