Our landscapes have been graced by the beauty of lobelias for many years. There are both annual and perennial lobelias, native in many parts of the world, but this essay will focus on one of our natives, Lobelia cardinalis, Cardinal Flower.
This perennial, hardy from zones 5 to 7, is useful in bringing mid to late summer color to our gardens. Its bright red spike of tubular flowers, held well above the dark green, irregularly toothed foliage, can be seen from great distances in early August. I will never forget espying a stand of it across a rather large lake in England while the rest of the flora appeared as a green mass.
The cultivar ‘Fried Green Tomatoes’ is more vigorous than the species and throws up several spikes instead of just a few. If you love color, plant ‘Golden Torch’ which has bright chartreuse foliage but is similar in all other respects.
Lobelia cardinalis grows two to four feet tall but only two feet in diameter. It prefers moist soil in a site with full sun to partial shade and will disappear within a year or two if it is subjected to dry conditions. Frequently found in nature on stream banks, this is an excellent candidate for plantings near water features.
The combination of the color red and the tubular aspect of the flowers provides a strong attractant to hummingbirds and butterflies. Fortunately, it seems to be relatively impervious to deer and rabbit predation. You might not think of combining red and purple but I saw Cardinal Flower in a full sun planting with Liatris, Verbena bonariensis, and Lobelia ‘Fan Blue’ at Floriade a few years ago. That Cardinal Flower was a cultivar with dark foliage that is, sadly, not hardy for us.
This is another great native perennial for our gardens.