Dahlias come in one of the largest arrays of shapes, colors and sizes of any flower. Their size ranges from giant "dinner plate" to tiny pompon types. Dahlias make a splash as excellent cut flowers. Dahlias are generally treated like annuals in our Boulder climate. Their tubers can be dug in the fall, stored through the winter and started indoors in the early spring. As soon as all frost danger has passed, they may be planted outside again to give you beautiful color for another gardening season.