Theatrical dahlias may be making a comeback
Chapel Hill, N.C.
There's nothing subtle about dahlias. Today's hybrids are vivid, striking, bold composites that provide the most eye-catching displays at flower shows coast to coast. And they can do much the same thing in home gardens, too. The theatrical giants with their 12- to 15-inch blooms are spectacular additions to any large perennial garden. For small gardens or low borders, there are also mini-dahlias with 11/2- to 2-inch flowers produced on foot-high, shrubby plants. And dahlias come in all sizes between these two extremes.Skip to next paragraph
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Dahlia gardeners also have a wide choice in both colors and forms. These plants come in white, pink, rose, red, yellow, orange, lavender, purple, blends, and bicolors -- every color but a true blue. And while one grower will prefer the spiky cactus types, another might choose softly rounded decoratives, singles, or fully double balls, or anemone-flowered, peony-flowered, or orchid-flowered dahlias.
When I had a garden in Connecticut, I thought of dahlias as labor-intensive plants because, like glads and tuberous begonias, these summer-flowering tubers had to be dug each fall, stored carefully, and replanted in the spring. But while gardeners in the Northern tier of states must do this, it's not so for those in the South. Here in the Piedmont of North Carolina, dahlias can remain in the ground year after year, surviving nicely with only a light mulch for winter protection.
Prof. August De Hertogh, chairman of the department of horticultural science at North Carolina State University, contends that the dahlia ``is one of the most underused plants in the North Carolina landscape.''
The same may be true nationwide. Like hemlines and car sizes, plant popularity comes in cycles. Dahlias have not been in vogue for a while, but I suspect they will benefit from the recent nationwide resurgence of interest in perennials -- particularly in the warmer parts of the United States, where they can be treated like herbaceous perennials.
Culture for dahlias is reasonably simple. Plant the tubers two to three inches deep in a well-tilled bed enriched with generous amounts of compost or rotted manure. Stake the tall varieties at planting time. Water and feed generously throughout the growing season. Professor De Hertogh recommends using a balanced fertilizer at least once a month and preferably twice.
If you are gardening in one of the Northern states, plant your dahlias in full sun. Southern gardeners, on the other hand, should try to provide some midday shade.
When the new plants have two or three sets of true leaves, pinch out the tip to promote branching and produce a more compact, attractive plant. The tall varieties will benefit from a second pinch when the side shoots produce three sets of leaves.
Several flower buds will form at the tips of each growing shoot. While these buds are small, you have a choice. As with peonies, mums, and roses, you can leave all the flower buds on the plant and enjoy a colorful display of numerous, small flowers. For cut flowers with long stems or for exhibition dahlias, remove the side buds on each shoot and leave only the terminal bud to produce one magnificent flower per stem.