Cardinal Flower--A Moisture-Loving Native: Texas Gardener

By Jan Pipher

Freelance Writer

There is a flower for every niche and here is one that is just right for the “moist, dappled shade” category. Gardeners in the eastern part of the state take wet/shade as a matter of course. Those of us elsewhere, however, tend to find our shady spots very dry in the heat of the summer and not shady at all throughout our (usually) wet winters. For those of you who have struggled with adapting perennials to the rigors of your particular Texas climate, take the happy path of least resistance – pick a native like Lobelia cardinalis.

Natives live here. They tolerate shady places becoming sunnier and sunny places turning shady; they hunker down in the dry spells and wait for moisture; they accommodate rapid temperature drops and prolonged searing heat. Cardinal flower, as it is commonly called, is a water lover, but if anything can make it in a dry stream bed, it will probably be this crimson flower that you will find blooming come fall.

L. cardinalis has beautiful, bright-as-a-cardinal, red flowers that bloom up a lengthening raceme from late summer until frost. The plant itself grows from 1 to 3 feet tall and a foot or less in diameter. During winter dormancy, lobelia dies back to a basal clump of leaves or disappears completely, then sends up one or more unbranched stems in late spring.

Bringing wild lobelia into the domesticity of your landscape can be a rewarding experience. First of all, its striking red blooms mixed among other water lovers, like cannas, elephant ears, Louisiana iris, loosestrife and horsetail, make a showy backdrop for a water garden. Cardinal flower will thrive in any available water – leaky hoses, down spouts, gray lines – it just has to be consistently wet. I take advantage, for instance, of the condensate water from my A/C unit; rerouting the line (downhill only) to a nearby planting of L. cardinalis. Or, if you live in the country and have a “constructed wetland” waste treatment system (see TEXAS GARDENER, September/October 2000). Lobelia cardinalis, along with other aquatic plants makes a showpiece flower bed while purifying your water at the same time. In a perennial garden, planted with flowers of varying water requirements, separate it from the xerephetic plants to a spot where it will receive water daily; morning sun/afternoon shade or dappled sun all day; and mulch it well during the heat to keep the soil cool and evenly moist. Set lobelia out in groupings of three to give it breadth as the stalks do not usually branch, and go easy on the fertilizer.

Flower gardeners are not the only ones drawn to the scarlet spikes of lobelia – pollinators of all sorts are attracted by its brilliant color to the nectar within each tubular bloom. Named as one of the top 10 hummingbird plants, late blooming L. cardinalis keeps the tiny birds coming to your beds when many of your other hummingbird-attracting plants are on the wane.

Two other color forms exist, known respectively as Lobelia alba (white) and Lobelia rosea (pink). Several hybrids of cardinal flower parentage are also available. ‘Queen Victoria,’ for example, with its striking burgundy foliage, is a well known (though not as hardy) nursery offering in the South.

Lobelia cardinalis is classified as a short-lived perennial, meaning that it comes back from the roots for only two or three years, rather than 10 or 15. But native lobelia has its own “plan B” survival system – it grows easily from seed. When the last flowers are in bloom at the top of the raceme, the older flowers at the bottom have already set seed. Gather the dry seed pods and sow them in the fall for a happy splash of red in your flower garden next summer.

Subscribe today!