Great Blue Lobelia has a long blooming period

Published 5:40 pm Friday, October 9, 2020

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By Helen Hamilton


Great Blue Lobelia

Lobelia siphilitica

A lovely plant late in the growing season, when plants with yellow flowers are usually prominent. Tall spikes of brilliant true-blue flowers grow on a stiff, unbranched, leafy stalk, 1-3 feet high. Flowers of this genus all have two narrow lobes or “ears” above, with three wider lobes forming a lip below. The 1-inch long violet-blue flowers of Great Blue Lobelia are striped with white on the three lower lobes, which appear more prominent than the lobes above. Leaves are alternate on the stem, finely toothed and pointed.

Great Blue Lobelia is a wetland native species, requiring wet to moist soil, fertile and loamy. The plant requires little maintenance, growing in part shade, but in full sun the soil must be consistently moist, as in rain gardens. The natural habitat is meadows, moist thickets and swamps from Maine to Manitoba and Colorado, south to North Carolina and Texas. While found in most counties of Virginia, it is infrequent in the Coastal Plain.

This clump-forming perennial has a long blooming period, from July through October. Also known as Blue Cardinal Flower, this plant tolerates conditions that are drier than those of the red species. This plant is a member of the Bellflower Family, the name suggesting a rounded corolla with a long neck. Bumblebees can access the nectar at the bottom of the tube-shaped flower while collecting pollen.

While the seeds are too small to be of use to wildlife, Great Blue Lobelia self-seeds and is easy to grow from seeds collected in the fall. Or by division — the roots make offshoots that can be separated from the main plant in fall or spring. Making cuttings from stems with two nodes is another method of growing more of these plants.

Other Lobelia species native to the Coastal Plain have much smaller flowers. Indian Tobacco (L. inflata) has been reported in every county of Virginia, growing in woodlands, roadsides, fields and wetlands. Nuttall’s Lobelia (L. nuttallii) is frequent in wet areas and roadsides. Downy Lobelia (L. puberula )is in every county other than those in the far northwestern area. Other species and cultivars are available in the nursery trade.

Early medical writers thought American Indians used the root primarily to treat syphilis, hence the species name siphilitica. While potentially poisonous, the American Indians used root tea for syphilis, and leaf tea for a number of illnesses, such as colds, worms, nosebleeds, coughs and headaches.

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