The stunning Cardinal Flower is one of our most famous native plants, and usually called Americas most vivid native flower. Each summer, brilliant red Cardinal Flower lights up the August woods all over the east, and new generations of hikers are always thrilled when they come across it in our forests. Of course, the fact that it does not bloom in spring, but adds color later, makes it of huge value in a wild garden.
This famous plant is native all the way from Quebec and Minnesota south to Florida and Texas. It is so beautiful it is over picked and now quite rare in some areas. However, if conditions are right (wet, mostly) it will grow easily, even in full sun, but is usually found as a woodland beauty along streambanks or near ponds where the soil is always moist. It is even happy growing right in the shallow water of small creeks and brooks.
This tells you that you must supply constant moisture for Cardinal Flower, and if you do, the rewards are spectacular.
Growing Lobelia cardinalis Allen Armitage, the famous perennial expert writes in his Armitages Native Plants that Cardinal Flower is a short lived perennial but if...(conditions are good)... it will return many years. This is correct. It is not difficult to grow at all; it is simply difficult to maintain a clump of plants over the years, unless you are attentive. Armitage tells us he believes the plants do best in full sun. I found the opposite growing them in Vermont. But sun or shade, the most important item is the moisture. The roots should never really dry out. We had many growing along a small brook in the middle of a wooded garden (See photo above). All went well, and the plants performed with bigger and bigger flower spikes each year, until.....we had a spring flood one year. The brook raged out of its banks, and the rushing water uprooted all the plants and swept them away. So that year, we had to start over with new plants. They have very shallow roots, and come out of the mud easily.
This wild beauty is one that you must watch, and you'll learn to love it. It grows quickly and easily, but it has two very powerful enemies--people who love to pick it, destroying the display, and either too little or too much (rushing) water.