Not many plants this side of the sunflower have blooms the size of a 12-inch dinner plate. The dahlia does… not to mention marigold-sized balls, pompon-shaped ones reminiscent of mums, and versions with flowers that look like orchids, peonies, water lilies, anemones and even cactuses. Few flowers come with so many different looks and in so many colors and bicolors. The symmetry of petals in many varieties, is absolutely stunning! The vast variety explains why this Mexican native spawns collectors – once including France’s Empress Josephine, who tended her own collection when dahlias were valuable enough to be traded for diamonds. Another dahlia draw is that they bloom from mid-summer until frost, making them a good choice for late-season color.
How to grow dahlias
Dahlias grow from tubers, which are oblong, underground stems that look like a sweet potato. Plant them 6 inches deep in spring, after danger of frost has passed.
Fertilize twice – once soon after the shoots emerge and again in early summer. Also, keep the soil damp but never soggy as those tubers are prone to rotting in cold, wet soil.
Snip a few stems for cut flowers, and grow dahlias in pots if you don’t have a sunny spot in the yard. After fall’s first light frost browns the foliage, cut the stems to 6 inches and wait three to five days before carefully lifting the clump with a digging fork. Rinse soil off the clumps, let them air-dry for another three to five days, then snip off each tuber close to the stem. Store the tubers in bags of vermiculite, sawdust or sphagnum moss over winter in a cool, dry spot.
Most dahlias grow tall and will flop if you don’t stake or cage them. Support them at planting – not after they flop – and be careful not to ram your stakes through the tubers. To get really big dahlia flowers, pinch off all but the center bud as you see three-bud flower clusters forming at the stem tips. You’ll get fewer flowers, but the ones that grow will be bigger and showier.