Lobelia: The l‘Obel Garden Prize
Porterbrook Native Plants
Matthias de l‘Obel, born in Lille in 1583 and who died in 1616, moved to England and became physician and botanist to James I. The plant genus Lobelia and the botanical family Lobeliaceae are named in his honor. L’Obel never beheld the plants that bear his name, but I am sure that he would appreciate and acknowledge their beauty.
Cardinal Flower (Lobelia cardinalis) and Great Blue Lobelia (Lobelia siphilitica) are two of our most beautiful wildflowers. Both species inhabit wet areas, especially along stream banks. What many gardeners do not know is that there are several other species of Lobelia that can be used successfully in their native plant landscape design. Most of these Lobelia species grow in meadows, ditches, swamps and occasionally on rocky hillsides. They offer a range of colors from the brightest red to the purest white.
Lobelia species are easily identified by their bilaterally symmetric flowers which possess a two-lipped corolla. The upper lip has two lobes, while the lower lip has three spreading lobes. The five stamens are united within a tube. The pollen is at the bottom of the tube. When pollinators (frequently butterflies) visit these Lobelia species, the pollen drops onto their backs.
Like so many of our native plants, Native Americans and early settlers found medicinal uses for the Lobelia species. A word of caution: all
Lobelia plants are considered to be toxic. Never use them as a home remedy. Lobelia inflata (Indian Tobacco) is a strong emetic, expectorant and sedative. Native Americans smoked its leaves for asthma, bronchitis, and sore throats. It was also used to induce vomiting, thus its nickname “pukeweed.” The roots of Lobelia siphilitica were used by Native Americans to make a tea for syphilis. Tea made from the leaves was used for colds, fevers, worms, croup and nosebleeds. Tea made from Lobelia spicata (Pale-spiked Lobelia) was used by Native Americans as an emetic. And a wash made from the stalks was used to treat “bad blood” and neck and jaw sores. Lobelia cardinalis had similar properties, but was considered much weaker and therefore was not used widely.
Lobelia cardinalis and Lobelia siphilitica are the two most frequently grown flowers in this genus. The common name, Cardinal Flower, refers to the bright red robes worn by Roman Catholic cardinals. It grows throughout the eastern United States and is usually found in wet soil, stream banks, and roadside ditches. The first time you come upon this plant in a half-shaded spot along a stream you will never forget the fiery redness that is accentuated by the shadows. I have grown this plant successfully in good garden loam in full sun, but it never attains the vivid red flowers when in its natural habitat. It is an erect and typically unbranched perennial that normally reaches four feet, making it one of the largest Lobelia and the only one with red flowers. The leaves are alternate, lanceolate (about six inches) with toothed margins. Ruby-throated hummingbirds usually pollinate the bright red flowers, which grow in a spectacular raceme. On rare occasions, you might find a pink or white form. Long-tongued butterflies, such as the Spicebush Swallowtail, Eastern Tiger Swallowtail, Pipevine Swallowtail, Cloudless Sulphur, and Dogface butterflies will also visit the flowers.
Lobelia siphilitica (Great Blue Lobelia) grows in swamps and along stream banks throughout the eastern United States, west to Wyoming and south to Texas and Georgia. The species name, siphilitica
, comes from Latin “of syphilis” and refers to the use of the root to treat syphilis. It was an ineffective treatment. Bees pollinate this species. Great Blue Lobelia is a robust and erect perennial that can reach four feet but usually grows two feet in height. The flowers are a bright blue with a touch of white. Although this plant prefers moist soil, I have also grown it in good garden soil in full sun.
Lobelia puberula (Downy Lobelia) possesses a fine-hairy stem, with toothed leaves, and a one-sided raceme of purplish blue flowers. Unlike Lobelia siphilitica, they lack the inflated tube and striping. Downy Lobelia enjoys open woods and drier soils, usually growing along the wood’s edge in dappled shade. Although it grows erect, it has a tendency to flop over and rest on neighboring plants. Nevertheless, it is a welcome addition to the wildflower garden.
Lobelia spicata (Pale-spike Lobelia) occurs from Alberta and Quebec south through most of the eastern and mid-western United States and west to eastern Texas. It is an erect and unbranched perennial that reaches two feet. Approximately twenty bluish-white flowers are scattered along a nearly leafless stem. A rosette of club-shaped leaves grows at the base of the stem. The fruits are tiny, round capsules filled with chestnut brown seeds. Lobelia spicata grows in moist or low prairies, but also inhabits meadows, glades, barrens, and thickets. Like other Lobelias, it contains poisonous substances formerly used in medicinal remedies and as an agent to discourage the use of tobacco.
Lobelia inflata (Indian Tobacco) is an annual and can become quite weedy. It is by far the most common of the species and is frequently found in disturbed areas. Indian Tobacco is easily identified because of the inflated seed pods that develop along its stem. The flowers are typically light blue to white. And the stem is long, hairy, and branched. Because of the toxicity of all parts of this plant and its tendency to become weedy, it should not be planted in the garden.
The remaining species of Lobelia are extremely rare and endangered or are endemic to certain parts of the eastern United States. These species need to be protected and enjoyed during visits to natural areas. Lobelia kalmii (Ontario Lobelia) grows in damp soil-- usually in calcareous regions-- in meadows, bogs and ditches. The flowers are white to blue with a conspicuous white eye-spot. Lobelia boykinii (Boykin’s Lobelia) is semi-aquatic and grows in swamps and cypress ponds from the coastal plain of Delaware to Florida. The lower portion of the plant is seasonally submerged in water. The flowers are blue to white, and it is the only Lobelia species that possesses rhizomes. Boykin’s Lobelia is endangered throughout its entire range. Lobelia dortmanna (Dortmann’s Cardinalflower) is strictly an aquatic plant found along the margins of ponds and lakes. The flowers are light blue to white and widely spaced on long flower stems. The upper stem is leafless, while the lower leaves are under water forming a dense basal rosette. The plant is usually 18 inches in height. Lobelia nuttallii (Nuttall’s Lobelia) grows in various moist soils from pine savannahs and pocosin to low woods and prefers sandy soil. The small flowers are blue with a white center and two small, green spots at the base of the lower lip. The plant ranges from eight to thirty inches in height. Lobelia elongata (Longleaf Lobelia) has a long and wispy stem. The flowers are a deep blue and are confined to one side of the stem. The lower leaves are grass-like with sharply toothed outer margins. It prefers wet habitats such as swamps and wet meadows. A similar species, Lobelia glandulosa (Glade Lobelia), is fairly common in the coastal plain and eastern Piedmont. It is distinguished from Longleaf Lobelia by having long hairs on the inside of the lower lip of the corolla. Lobelia appendiculata (Pale Lobelia) has a slender, erect stem reaching about two feet. The flowers are pale blue to white. It is widely distributed in pinelands and prairies in the Gulf Coast states. Lobelia appendiculata var. Gattingeri (Gattinger’s Lobelia), named in honor of Augustin Gattinger a pioneer botanist from Tennessee, is a diminutive variety reaching only twelve inches. Gattinger’s Lobelia is an endemic found only in the cedar glades of the Central Basin of Tennessee, although there is a report of one population in Kentucky.
Folks living in or visiting Florida might have an opportunity to see three rare species of Lobelia. Lobelia floridana (Florida Lobelia) is native to Florida’s wet flatwoods, cypress pond margins, and bogs, especially in the central and western panhandle. Flower colors range from blue to pink to white. Lobelia homophylla (Pineland Lobelia) inhabits pinelands, fencerows, and roadsides, while Lobelia feayana (Bay Lobelia) grows mostly in pinelands.
Lobelias should be incorporated into any native wildflower garden or landscape. They provide a vivid range of colors while in bloom, and they attract numerous pollinators to gather their nectar. We also need to take immediate steps to protect all of the species facing loss of habitat, especially those growing in and dependent upon wetland conditions.