The cardinal flower's brilliant blossoms are adapted for pollination by hummingbirds.
Cardinal flower is a short-lived herbaceous perennial that grows in clumps usually 1-3 ft (0.6-0.9 m) )tall and a foot or less in diameter. The stems and leaves have a purplish tint and no wildflower is brighter red. Cardinal flower spends the winter as a basal rosette of 5-7 in (13-18 cm) elliptic leaves flat on the ground. In spring it sends up one or more unbranched (sometimes branched) stems with smaller leaves. By mid-summer each stem develops a terminal raceme a foot or so long of brilliant scarlet-red flowers, each about 1-2 in (2.5-5 cm) long. The flowers are tubular and bilaterally symmetrical with two lips. The upper lip has two more or less erect lobes, and the lower lip has three lobes that are spread out horizontally or dip downward. Flowers continue to develop at the tip of the lengthening raceme until frost.
Several cultivars have been selected, including 'Alba' with white flowers, 'Twilight Zone' with pink flowers, and 'Angel Song' with salmon and cream flowers. Also, cardinal flower is a parent of several hybrid lobelias including Lobelia X speciosa which has many named cultivars, including 'Russian Princess' with purple leaves, and 'Queen Victoria' with reddish leaves, and Lobelia X gerardii also with several named cultivars.
Cardinal flower grows in moist meadows, bogs and along stream banks in eastern North America from New Brunswick west to Minnesota, and south to central Florida and eastern Texas. In some areas it is very abundant, forming mats of floating vegetation and even clogging waterways. There are several other species of Lobelia in North America, but this is the only one with red flowers.
Culture Light: Full sun to partial shade. Moisture: Cardinal flower requires moist soil. It can even tolerate flooding but not drought. You can grow cardinal flower in normal garden soil, but it must be watered regularly. Hardiness: USDA Zones 3 - 10. Propagation: By seed and by separating the basal offshoots. Cardinal flower will self sow in the garden under favorable conditions.
The cardinal flower's stems continue to grow throughout the season, constantly producing new flower buds at the tip.
Cardinal flower is a spectacular show along the edge of a pond or water garden. Don't be discouraged if you have a low, wet area: create a colorful perennial flower bed with irises, monkshood, cannas, ferns, horsetails, and masses of cardinal flowers.
Cardinal flower is pollinated by the ruby-throated hummingbird. They are attracted to it in droves!
Despite the fact that Native Americans used infusions and decoctions of cardinal flower to treat all sorts of real and imagined afflictions (including epilepsy, fever sores, parasitic worms, typhoid, witchcraft, and grieving sickness), the plant contains poisonous alkaloids and ingestion has caused deaths in humans.