Great Blue Lobelia

Aug 9

Written By Wheeler Wildlife Refuge Association

Lobelia siphilitica, Great Blue Lobelia, Blue Lobelia

Partly named in honor of the Flemish botanist and physician, Matthias de l’Obel (1538-1616), as well as for its earlier use as a treatment for syphilis, this is a blue flowered and shorter version of its red relative, Cardinal Flower (Lobelia cardinalis), and is sometimes called Blue Cardinal Flower.

Its flower size and shape so closely match the dimensions of bumble bees (their principal pollinator) this is often regarded as evidence of the mutualistic co-evolution of the two species (where species evolve, through many, many, many generations, in ways that benefit each other). Bumbles (bumble bees) transport pollen grains (yellow) gathered on the hairs and special structures on their bodies, and transfer these to the flowers of other plants as they visit and draw nectar from the other flowers. This allows the sharing of genes from one individual plant to another (cross pollination). Pictures show one nicely loaded bumble as well as their custom fit.

While hummingbirds are famously drawn to red flowers, they will also draw nectar from these, as well as many other non-red flowers. It is widely regarded that the color blue (as we see it) is of greatest interest to bees - this tidbit is the basis of a whole other amazing story!

In William Barton’s work, Vegetable Materia Medica of the United States, written in 1818, he indicates that this use of the root by various native Americans to treat syphilis was held in secret among them until sir William Johnson purchased it from them and made this known to the Europeans of the time. As reported, many eminent physicians of that time tried and failed to realize any success in confirming this as an effective treatment. William Bartram also indicates that native Americans used the root in combination with many other plants to treat syphilis (perhaps some essential information was strategically withheld?). That said, the plant contains many compounds of interest to science which are still being researched. One compound may have significance to gardeners: lobeline is said to deter herbivores. Due to lobeline or another compound we consider this a plant that is not typically browsed by deer or rabbits.