Lobelia Siphilitica


Lobelia siphilitica is the scientific name for a wildflower known as Great lobelia. It is a perennial flower that you can use in your wildflower garden to highlight borders. It is an excellent species for woodland gardens, according to the Wildflowers.org website, and is not a difficult flower to grow, requiring very little maintenance.


The flowers are tubular, possessing "lips" on the top and on the bottom. The upper part of the Great lobelia bloom has two separate segments, while the lip of the bottom divides into three. The flowers grow up and down the top part of the stalk amongst the leaves that protrude from the stem. They are a lavender blue color that attracts both butterflies and hummingbirds once they blossom out. The shape of the flowers and the features of the plant remind many of the cardinal flower, which is the only type of lobelia that has bright red flowers.


Lobelia siphilitica can grow as tall as 4 feet in some instances but averages between 1 to 2 feet in height. The leaves are anywhere between 2 and 6 inches long and the petals are up to an inch in length.


In the wild, Great lobelia, like most other types of lobelias, grows where the ground is rich and moist. This includes such settings as lowland woods, along the banks of brooks, streams, rivers and near wetlands. The geographic distribution of the Great lobelia encompasses most of the Eastern United States as far west as parts of Texas. It also grows well into Canada.

Time frame

The flowers of the Great lobelia will bloom from mid-July all the way through September, making it a fine choice if you want some color still around as other species are long past flowering or on the wane. You can plant Great lobelia in the middle of the spring from seeds or divide the rootstock and grow it in that manner.


The species acquired its not-so-desirable scientific name from the fact that at one time, the Native Americans felt it was a viable cure for syphilis, which it was not. The roots, leaves and stems of Lobelia siphilitica have alkaloids in them, which can result in vomiting, serious illness and even death if eaten in large amounts. Animals that consume large quantities of this plant suffer from poisoning as well, so be aware of this if you add it to your garden.

Keywords: Lobelia siphilitica, great lobelia, cardinal flower

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John has written thousands of articles for Demand Studios, Associated Content and The Greyhound Review. A Connecticut native, John has written extensively about sports, fishing, and nature.