August is not the time we identify with many specific plants in flower beds, as we do with daffodils in March.

Most of our color stems from the maturing annuals set out in spring and nurtured through the hot weeks of early to midsummer. These bedding pants - impatiens, begonias, coleus, pentas, lantana and more - reach their full beauty as late summer clamps down. Still, gardeners like surprises, and one fine perennial has the potential to do that beautifully, even in the heat and humidity of August.

This is an unusual, but not unknown perennial named Lobelia cardinalis, commonly called cardinal flower. It is a tall, vertical plant that bears spikes of scarlet red flowers in late summer. These flowers really stand out not just for their color but because their shape is so different.

Cardinal flower is a native of damp, shady woodlands of Eastern North America, from Canada to Florida. That makes it useful for Piedmont gardens with wet spots where creeks rise occasionally or downspouts gush during storms. It blooms best with some sunlight filtering through the canopy or at the edge of thicker woods. As a woodland plant, cardinal flower is accustomed to the rich, porous soil formed by decomposition of leaves.

That is not hard to emulate by working in a shovel or two of compost at planting time. The foliage will die down in late autumn or early winter when you can cover the root zone with a light mulch several inches deep that does not pack down, such as oak leaves or straw.

It is rather short-lived. A plant should be with you a few years. But the bloom lasts several weeks in August and perhaps a bit beyond. A wet summer really helps the plant develop. The spike of flowers will rise a foot or more, covered with bright red petals that stand out well, even in the shade. The petals split at the base on one side of each bud and form two symmetrical lips. The individual flowers open from the bottom, then up the spike in a botanical pattern called a raceme.

While cardinal red is the defining color of Lobelia cardinalis, you see it offered in other colors, such as white, salmon and pink. Garden centers that are well-stocked in perennials may have plants in bloom so your eye can guide your color choice. If you buy one now, plant it right away and water regularly through the summer and into fall.

If you are unaccustomed to this lobelia, start with a single plant which is lovely in bloom, especially if there are lush green ferns and hostas as background. A group of three or five is dramatic.