Common Name: Great Blue Lobelia

General Information

Lobelia siphilitica is a herbaceous perennial plant with frequently-branched, erect stems; it can grow around 50 - 150cm tall[].
The plant is harvested from the wild for local use as a medicine..

Known Hazards

The plant is potentially poisonous[].
Many, if not all, species in the genus Lobelia contain a range of piperidine alkaloids, particularly lobeline and lobelanine. If ingested, these can cause a range of symptoms including nausea, vomiting, diarrhoea, salivation, exhaustion and weakness, dilation of pupils, convulsions, and coma. Generally, the degree of toxicity is only moderate and plants are only harmful in larger quantities - indeed several species have medicinal uses and a few are even eaten as wild foods[]

Botanical References

,

Range

Central and Eastern N. America - Manitoba to New Brunswick, south to Texas and Georgia.

Habitat

Moist woods and marshes[].

Properties

Medicinal Rating
Habit	Perennial
Height	1.00 m
Pollinators	Hummingbirds
Cultivation Status	Ornamental, Wild

Cultivation Details

Requires a moist soil, succeeding in full sun or partial shade[, , ].
A very ornamental plant[]. It will usually flower in its first year of growth from seed, but is short-lived unless divided frequently[, ].
Plants will often self-sow in cultivation[].

Edible Uses

None known

Medicinal

The root is cathartic, diaphoretic and emetic[, , ]. It is used in the treatment of dropsy, diarrhoea, stomach complaints, syphilis and dysentery[, ]
A poultice of the root has been applied to sores that are hard to heal[].

The leaves are analgesic and febrifuge[]. An infusion has been used in the treatment of colds and fevers[].
A poultice of the crushed leaves has been applied to the head to relieve the pain of headaches[].

At one time in N. America the root of this plant was believed to be effective in the treatment of VD[, ]. When used in Europe, however, it was found to be ineffective[]. This might have been because the N. American Indians used the fresh root (which still contained the volatile oils) and also used it in conjunction with Podophyllum peltatum and Prunus virginiana, and then dusted the ulcers with the bark of Ceanothus americanus[].
It was believed by some native North American Indian tribes that if the finely ground roots were secretly added to the food of an arguing couple then this would avert a divorce and they would love each other again[].

A homeopathic remedy is made from the roots[].

Other Uses

None known

Propagation

Seed - best sown as soon as it is ripe in a cold frame and only just covered[, ]. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Division in spring[].
Basal cuttings in spring[]. Harvest the shoots when they are about 10cm long with plenty of underground stem. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.
Layering in moist sand, it forms roots at the nodes[].