The Georgia Native Plant Society is pleased to announce that cardinal flower (Lobelia cardinalis) has been selected as the organization’s 2006 Plant of the Year.
Cardinal flower is one of our most recognizable wildflowers, for it bears a stunning, upright stalk of brilliant red blooms that is a standout in the garden or in its native habitat. This North American perennial was so admired by early explorers of our continent that it made its way to Europe in the 17th century. The name of the genus honors Matthias de l’Obel, who was a Flemish botanist; cardinal flower’s specific epithet reflects the bloom’s similarity in color to the scarlet robes of cardinals.
Cardinal flower is in the bellflower (Campanulaceae) family, though the flower is not what we think of as a typical bell-shaped form. Instead, the 1- to 2-inch bloom is bilaterally symmetrical with two lips. The upper lip has two lobes, and the wider, spreading lower lip has three. Five stamens unite around the style in a slender formation and extend upward from the mouth of the flower.
These blooms are densely borne on erect, unbranched spikes that typically reach 2 to 4 feet tall. Along the stem are interspersed alternate, elliptical to lanceolate leaves with an irregularly toothed edge. Blooming begins in mid to late summer and extends a month or more, with flowers opening sequentially up the spike. After blooming, a low rosette of 2- to 6-inch long leaves remains evergreen throughout winter. Offsets will develop from this crown, providing more plants for the garden.
Flowers are followed by round seed capsules that turn from light green to brown as the seeds mature. The seeds are small, numerous, and cinnamon-brown in color, and they remain in the capsules until they finally sift out through small holes in the top. Cardinal flower will readily self-seed if conditions are to its liking.
Cardinal flower’s preferred habitats are moist to wet areas, such as stream banks, damp meadows, marshes, roadside ditches, and low woodlands. It has an extensive natural range, occurring throughout much of the eastern half of the United States and into Canada.
The brilliant red blooms prove irresistible to hummingbirds, which are cardinal flower’s main pollinator. In a mutually beneficial arrangement, as the hummingbird sips nectar from within the base of the tubular corolla, the anthers dangle above the bird’s head, depositing pollen there, which is then transferred to the stigma of the next visited flower. The flowers are also popular with long-tongued butterfly species.
Cardinal flower can be grown in average garden conditions, but to keep it happiest, take a cue from its natural habitat and provide ample moisture. It will even tolerate occasional standing water, making it useful for areas with drainage problems. Cardinal flower prefers garden sites with sun to light shade, though it will appreciate protection from intense afternoon sun.
In the garden, cardinal flower mixes well with plants that require similar conditions, including its relative, great blue Lobelia (Lobelia siphilitica), Boltonia (Boltonia asteroides), New York ironweed (Vernonia noveboracensis), scarlet rosemallow (Hibiscus coccineus), swamp sunflower (Helianthus angustifolius), turtlehead (Chelone spp.), and green-head coneflower (Rudbeckia laciniata). Cardinal flower’s brilliant color makes for a stunning focal point wherever it is placed. It also adapts well to container cultivation if adequate water is provided.
Cardinal flower is easy to propagate by seed, cuttings, or division of mature plants.
Prepared by Mary Pyne Tucker
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