Plants of the Eloise Butler Wildflower Garden

Lobelias have a tubular shape corolla splitting into 2-lipped flowers with a 2-lobed upper lip and a 3-lobed lower lip. Great Blue Lobelia is a native erect perennial growing from 1 to 4 feet high on stems that seldom branch below the inflorescence. Stems are stout and either smooth or with sparse fine hair, but usually with hair in the inflorescence.

Leaves are alternate, oblong to oval, (broader than those of the Cardinal Flower) and tapering to a stalkless base in the uppers while some lower leaves may have a short stalk. Leaf margins can be entire but usually have a broadly toothed edge. Surfaces are usually smooth, without hair, the underside a paler color than the upper side. A basal rosette is first seen in the Spring.

The inflorescence is a crowded raceme, 4 - 12 inches tall, of stalked flowers, the spike rising above the leaves.

Flowers: The 5-parted flowers of this plant are about 1 inch long with hairy stalks. The green calyx is very hairy and has 5 pointed long lobes. The corolla tube is bluish-purple, inflated and with darker color nerves underneath. (White albinos are known to occur.) The tube opens to an upper lip with 2 lobes and a lower lip with 3 lobes, all of which have pointed tips and are deeply split between the lobes. Five stamens are united around the style and rise up between the upper lips and then make an abrupt downward turn near the tips. A green leaf-like bract is subtended to each flower. (see Eloise Butler's notes below).

L. siphilitica is gynodioecious, that is a certain percentage of plants will have sterile male parts and are thus female only. These plants can be determined by papery white anther tubes which are without pollen instead of bluish ones.

Seed: At maturity hundreds of oblong, ribbed, brown seeds form in a 2-celled capsule, that opens at the top. Seeds require 60 days of cold stratification and require light for germination. Seeds collected in the fall can be planted immediately and let nature do the work.

Studies have shown the plants that are female only show no difference in fruit sets and seed production. This is completely different from the Pale-spike Lobelia, L. spicata, which also has male sterile plants, and those male sterile plants produce more fruit capsules, more seed per capsule and better germinating seeds. A study done by Miller and Stanton-Geddes published in 2007 looked at the frequency of L. spicata and L. siphilitica plants to have only female flowers and the affect on seed production. [PDF of Study] This study and others have shown that the number of female only plants in a given population is dependent on latitude - the further south, the greater percentage of female only plants.

Varieities: Two varieties of L. siphilitica are found in Minnesota: Var. ludoviciana and var. siphilitica. The former is considered a western version in North America with less hair, leaves up to 3/4 inch wide and mostly hairless and fewer flowers. The latter is shown here in the photos, and is considered an eastern variety that has hair on the flowers and in the inflorescence, wider leaves and more flowers. According to the DNR plant surveys there is overlap in their ranges and both varieties are found in a number of metro area counties.

 

Habitat: Great Blue Lobelia grows from a rhizomatous root system. Separating and planting the basal rosettes of mature plants will also produce new plants. These grow from the plant's rhizomes and separation can be done fall or spring. Stem cuttings can also be propagated. All together, a versatile plant to grow. Like the Cardinal flower, this Lobelia prefers a wet to moist soil and full to partial sun.

Names: The genus Lobelia is named after the Flemish botanist Matthias de l'Obel (1538-1616), who, when he moved to England as physician to James I, anglicized his name to Matthew Lobel, hence "lobelia." The species siphilitica, is a reference to the old folk medicine belief that extracts made from the plant could cure syphilis.

The author name for the plant classification - 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. The family name for this plant is changing based on the work of the Angiosperm Phylogeny Group; many sources, including Minnesota authorities at the U of M Herbarium, now list this plant in the Lobeliaceae family whereas USDA still maintains it in the Bellflower family (Campanulaceae).

Comparisons: On the five species of Lobelia found in Minnesota, none of the others are likely to be confused with the dense spike of blue flowers and the dense leaves of this species. The other species located in the Garden is the Cardinal Flower, L. cardinalis.