Dahlia growing tips

The diverse dahlia boasts flower forms that mimic everything from pompons to waterlilies — and in just about every color. In Minnesota where the ground freezes, dahlias are cultivated as annuals, which bloom from the end of July to the first frost. Gardener Mary Ann O'Brien shared her best tips for growing beautiful dahlias:

• The bold "dinner-plate" size dahlias can be enjoyed from a distance. The smaller varieties are ideal for cut flowers for wedding bouquets and table centerpieces.

• O'Brien plants a sturdy stake and small tomato cage with every tuber to support the heavy plants.

• Dahlias are sun lovers but they will produce flowers with only eight hours of sun a day, especially if it's morning sun.

• Dahlias are heavy bloomers so leave plenty of space between them. If you continue to deadhead the flowers, they will rebloom. O'Brien mixes 'State Fair' zinnias with dahlias for bold color from August until frost.

• You can buy dahlia tubers in spring, but if you have favorites, you'll need to "overwinter" them. Be forewarned that the process is time-consuming and requires storage at about 45 degrees.

• Favorite grower: Swan Island Dahlias in Oregon.

• Helpful resources: University of Minnesota Extension Service, extension.umn.edu, Minnesota Dahlia Society, minnesotadahliasociety.org, and American Dahlia Society, dahlia.org.

Lynn Underwood