Dahlias are one of the most popular and prolific summer bulbs, and have been winning the hearts of home gardeners for many years. So much hybridizing of new varieties has been done over the years that one can find dahlias in almost every color combination possible. Their long blooming season makes them a perfect addition to any perennial border, and their exotic looking flowers and brilliant colors will make any garden shine.
The flower shapes vary. You can find anemone-type flowers, frilly cactus-type flowers, decorative peony-type flowers, pom-pom shaped, low-growing dwarfs, mignon, water lily-shaped flowers, and even the giant dinner plate dahlias, whose flowers can reach 8″-12″ inches in diameter.
A member of the daisy family, this Mexican plant thrives in sunny locations and warm temperatures. Dahlia bulbs are not winter hardy; the first good frost will make them turn black rather quickly. The best time to plant them is in spring any time after the last spring frost.
Some gardeners will try to get a jump on spring by potting up their dahlia bulbs indoors 6 weeks before they plant them outdoors. You will increase the bushiness of the plant by pinching off the main growing tips three weeks after you plant-regardless of when you plant them. This helps develop more stems and a lot more flowers throughout the growing season.
Dahlias grow best in well-drained soil that has been well amended with an organic planting mix. When planting, make sure to cover the tuber (bulb) with at least 2 inches of soil (regardless of size). Don’t plant deeper than this, as it can reduce the flowering. Plant your tubers 12-18″ apart, with taller varieties on the higher end of that scale and shorter varieties on the lower end.
Dahlias are long-blooming plants that can provide color from June to October. Because they bloom so heavily, it is important to make sure to feed them on a regular basis with an all-purpose flower food.
To keep your dahlias healthy and producing flowers year after year, harvest them immediately after the first frost has blackened the stems. Remove the dead foliage down to the tuber and store in a cool, dry and frost-free location. Then plant them again outdoors each spring to enjoy another season of dazzling color!