The genus Lobelia is truly an all-American flower – there are species that bloom red, white and blue! It is also a genus with wide adaptability that, in general, enjoys a moist area, but some species can adapt to drier conditions. Most species flower best in full sun.
Lobelia is part of the Campanulaceae family which is the Bellflower family. They share the trait of milky sap (pull a leaf off to see) with many other members of that family. They have another unusual trait: they have resupinate flowers. This means that their flowers are inverted – what appears to be the top of the flower is actually the bottom. You can see in this picture that they have an “upper lip” of two petals and a “lower lip” of 3 petals. In reality, the lip with 3 petals is the top of the flower which has been inverted 180 degrees.
The blooms open from the bottom up, seeds forming in the lower capsules even as the plant is still blooming.
The genus is named after the Belgian botanist Matthias de L’Obel (1538-1616). While members of the Lobelia genus can be found in temperate regions worldwide (yes, there is a Chinese one!), the red-flowered species, Lobelia cardinalis, was found in North America in the early 1600’s. Seeds of this beautiful flower were taken back to Europe in the mid-1620’s where it earned the common name Cardinal flower. This species is one of the most cultivated members of this genus today.
Pink flowered forms like Lobelia x 'Ruby Slippers' are hybrids of L. cardinalis and L. siphilitica.
Ok, enough with this gorgeous red flower - I promised you red, white and blue and you shall have it! The white flowering forms include the annual species Lobelia inflata, otherwise know as Indian tobacco, although some plants appear to be a very pale blue. The species name comes from the inflated appearance of the seed capsule.
Another white flowered species is the perennial Lobelia spicata, found in my area in fields and on roadsides. The long slender raceme of flowers provides for a very long bloom period. My pictures really do not do it justice - it is a very graceful plant. This site has very good pictures.
I collected some of the seed this year and hope to grow it for myself next year.
Lobelias in general do not have "pretty" foliage. The leaves are usually rather coarse looking, often dull and sometimes with rough edges. I caution those that grow it for the first time to expect a weedy-looking rosette of leaves at first and to be careful not to weed it out by accident.
|Lobelia cardinalis rosette|
Also, don't let leaves or mulch cover the rosette over the winter or the plant may die.
The blue species of Lobelia are quite spectacular in their own right. The "Great Blue Lobelia" is Lobelia siphilitica and it is a tall and handsome plant. It prefers moist places, and provides brilliant color to the mid-summer garden. I do not have it myself; the pictures here are from the gardens of friends.
photo by C. Lim
I do have the later blooming blue species, Lobelia puberula. This species can handle drier conditions; in fact, we have found it the most in a full-sun field on a particular construction site. The species name "puberula" indicates that it has some fine hairs on parts of the plants, and they are visible even to the naked eye on the stem and leaves. The common name is Downy Lobelia. I find the bloom to be much softer in color and texture than the Great Blue.
Consider adding Lobelia to your plantings. Come late summer, you will be very glad you did.