I first saw cardinal flowers growing in a drainage ditch along a farm field. Their intense red took my breath away, in part because of their surroundings.
This was no well-tended, perennial flower border, where colorful flowers would be expected. Growing along that ditch, those cardinal flowers were "mere" wildings. What's more, they were blooming in deep shade, a place usually lit, if at all, by white flowers.
The beauty of those cardinal flowers was not in their profusion of blooms but in the purity of their color. The red blossoms lined up along spikes a few feet high, their petals splaying out like small, cut paper fans.
Such purity of color is rare among plants. The blue Himalayan poppy is another plant renowned for intense color.
Such flowers must be used thoughtfully in a garden for they easily clash with other colors. The thing to do is ease the transition to other parts of the color spectrum with plants whose blossoms are less pure of color, bridging the gap from cardinal flowers to blue delphiniums with, for example, purple delphiniums. Or use white as a peacemaker.
BRINGING CARDINAL FLOWERS HOME
Clashes or not, I decided that I wanted to enjoy cardinal flowers closer to home. So I purchased seeds. They sprouted and grew readily, even bloomed by the end of their first season. Alas, these particular flowers were pretty, but their color was cooled down by a bit of blue mixed in with the red. Those seeds were one of many highfalutin cardinal flower hybrids now available in various shades of red as well as white and blue. I suggest growing the pure species (the wild form, Lobelia cardinalis) with the pure red color.
Cardinal flowers are easy to raise from seed. Buy the seed or collect it from wild or garden plants. The seeds are easy to collect because cardinal flower plants are usually maturing seeds even as they are flowering.
Now is an ideal time to plant cardinal flower seed. Seeds sown in the garden or in seed flats and only slightly covered, to let some light in, will sprout within a couple of weeks.
Keeping cardinal flowers going year after year is much harder than getting them started from seed. Although technically a perennial, this plant is a short-lived one, dying out after two or three years. It's possible to keep it going by renewing it every couple of years; just dig it up and cut out the younger, more vigorous parts of the clump for replanting.
Good growing conditions also help keep cardinal flowers going longer. That first wild plant I saw spelled out the plant's likes: shade and constantly moist, acidic soil. Cardinal flower will thrive in sun, too, blossoming more profusely, as long as its "feet" stay wet and summer weather is not too hot. It likes a mulch of leaves, straw or compost -- not over its head in winter, though, or rot results.
Even if cardinal flowers are fussy, they are worth growing. The blooms last till frost, and are livened further by the hummingbirds they attract. Cardinal flowers also make a nice cut flower if the spikes are cut just as the first blossoms on it open.
I, for one, am going to put in my order for seeds today, spurred on by plants I spotted only last week -- growing in a ditch in the shade, again. Or maybe I'll just collect seeds from these wildings.