FOR SOME, IMPATIENS are far too common to even consider; for others they are a godsend. They are very common--the single-most popular flower grown in this country--but that is for good reason. They are the only flower that thrives where there is little light. No green thumb is required. And if they look a little like they are molded from plastic, it is because they nearly always look good and are nearly always in bloom. In many gardens, they are the only flower that still looks good late in the year. You can't go wrong. Almost.
The one mistake made with impatiens is leaving them in the ground too long. Many gardeners have learned that impatiens can last longer than a season--but impatiens really should be replanted every year. True, they can be left alone or cut back and they will last into the next year or even longer. But after that first season they become increasingly leggy and flowerless. In impatiens plantings designed by Linda Cooper, the color coordinator for Roger's Gardens Colorscape in Corona del Mar, the impatiens are pulled out of the ground in October or November and replaced with Primula obconica , which looks good all winter. In the spring, out comes that common primrose and in go a new batch of impatiens. It's a neat switch, because the obconica primroses are similarly colored and grow under the same conditions as the impatiens.