Great Lobelias—Red, White And Blue - flower gardening - Brief Article

Flower & Garden Magazine, July, 2000 by Christine Beckert

The woods in August are a green place--until you come `round a bend in the path and find a sunny spot by the stream where dazzling red spikes will stop you in your tracks. Or perhaps it's blue spikes you'll see on the shore as you paddle down a slow-moving river. Dotted among either of these you may well find clusters of brilliant white, immodestly pure. You've stumbled across lobelia, and you'll never forget that spot.

Members of the bluebell family, lobelias are easy to recognize by their flower stalks with simple, alternate leaves, usually toothed; the flower itself is a five-petaled tube, the three lower lobes large and spreading, the upper two small and curved back. The flowers grow in a raceme, an unbranched stalk that blooms from the bottom up.

Cardinal flower (Lobelia cardinalis), a name honoring not the bird but the robes of church prelates, is unquestionably among the most beautiful and beloved of North American wildflowers. But it's also a marvelous garden plant, providing drama and beauty in August and attracting hummingbirds like a magnet. I grow it on a woodland edge, in a traditional border, and in a non-traditional rock garden--a rocky mound capped with a birdbath where I grow short plants of any provenance, not just alpines.

Short plants? Cardinal flower? True enough, the flower spikes can grow up to four feet tall, but judicious pinching in early summer keeps the bloom to about a foot.

Great blue lobelia, (Lobelia siphilitica) can grow to three feet. The flowers are anywhere from pale to bright blue, equally lovely against a white house wall, a clump of ferns or the dark mass of the woods.

Blue lobelia self-seeds prodigiously--it's listed as a rare species here in Massachusetts--but I can't imagine why, since every year it produces enough babies for generous distribution throughout the garden and among grateful friends and relatives.

In any collection of red or blue lobelia, whether in the wild or in your garden, you're apt to find some natural sports of pure white. If you want more of this beauty, you'll have to divide the rosettes in spring or take stem or root cuttings in summer, as it doesn't come true from seed. Coddling the white form is definitely worth the effort. A mixed strand of red, white and blue lobelia is spectacular, not to mention patriotic, and will dispel for all-time the idea that a late summer garden is a dull one.

Lobelias grow in moist places in the wild, in light shade or filtered light, but also in wide-open wet meadows, and such spots are what they like in the garden, too. Blue lobelia is more shade- and drought- tolerant than cardinal flower, but both appreciate a targeted drink of water in dry stretches, especially when grown in full sun. Both species are listed as hardy in Zones 3-9, but cardinal flower is also often described as a short-lived perennial. If you plant three, you might get only one or two back the following year, sometimes because unseasonable warmth stimulates growth too early. The survival rate goes way up if you cover cardinal flower with a loose mulch, such as straw or evergreen boughs; heavier mulches are not recommended, since they can promote winter rot.

Lobelias are widely distributed, though needless to say they should not be picked in the wild. Cardinal flower ranges from Quebec to Minnesota, south to Florida and Texas; great blue lobelia ranges from Maine to Manitoba, south to North Carolina, Alabama and Texas. Other American lobelias, almost all of them appearing on regional lists of favorite wildflowers, include Indian tobacco (Lobelia inflata) in the East and L. dunni in the West, both with pale violet flowers; the coarse but long-blooming L. fenestralis of the Southwest; L. appendiculata on the prairie, which unlike most lobelias grows in spring and early summer; and L. dortmanna, an aquatic curiosity that projects only its leafless flower stalk above northern pond waters.

L. cardinalis and L. siphilitica remain the species of most interest to horticulturists, along with the more tender L. splendens of Mexico. Hybrids of these species, grouped as L. x spesiosa and L. x gerardii, include various hues of red (the cultivars `Bee's Flame' and `Dark Crusader'), pink `Rosenkavalier,' purple `Russian Princess' and salmon `Angel Song.' There's even a bicolor, `Monet Moment,' with striking rose-striped white flowers that are extremely beautiful.

Species lobelias need little care--I give mine a generous helping of compost when I plant them and then just a little organic fertilizer in spring--but the hybrids tend to be heavier feeders and benefit from biweekly fertilizing through midsummer.

None of these perennials should be confused with the popular annual lobelias, primarily low-growing cultivars of the South African L. erinus. These are offered in all the lobelia colors and widely used as edgers and container plants.

In my judgment, however, neither the perennial cultivars nor the foreign annuals outshine our beautiful native gems. L. siphilitica may have snagged the honorific "great" in its common name, but all of the lobelias, red, white, blue, and even the more modest species, are a great strand of our American heritage and a great addition to any garden.