Latin name Dahlia sp., tuber-grown dahlias are typically taller with thick stems and require staking. Plants make a serious statement and can be made a central focal point of bed design. Dahlias are octoploids, meaning they have eight sets of homologous chromosomes; this is four times the number of chromosome pairs that most plants have. This results in a wide range of genetic expression that includes many colors and forms.



Native to the highlands of Mexico and Guatemala, they were considered a useful edible plant in the ancient Americas for their large, edible tubers. They were not initially recognized as a particularly special plant in Europe until the full range of genetic potential was realized. This created a breeding frenzy, and the dahlia was reimagined into a massive range of colors, forms and sizes!



Ornamental. Edible flower petals. Beds, borders, cut flower garden, containers, cottage garden.



Dahlias produce a large storage piece called a tuber. This is located at the base of the plant and is NOT the roots. When tubers arrive in the mail, they will be in a semi-dormant stage or in the phase of "waking up" from the winter. Each tuber should be comprised of a "toe," or storage piece, and at least one "eye," which is a growth bud much like a potato. In winter this eye will recess and become nearly invisible, but as the tubers break dormancy the buds will swell. Since tubers vary in size, dig a hole deep enough to keep tuber covered with buds pointed upward just bellow the soil line.



Plants prefer rich, well-drained soil and full sun. Space plants 18-24 inches apart. Tall, tuber type dahlias will require staking; otherwise they will flop over or split. Keep plants deadheaded and well watered, and feed with a well-balanced fertilizer. Pinch central node when plants reach 12 inches tall to encourage branching.



If soil is not well drained, standing water and excessive moisture can cause stem rot in dahlias. Be sure to prevent rot issues by providing well-drained soil. Powdery mildew can affect leaves, so provide adequate air circulation and water the roots rather than the leaves. Corn borers can invade the stems of dahlias. Take organic measures to prevent corn borers if they are a problem in your area.



It is not likely that you will get a reliable seed crop from the tuber-propagated tall type dahlias. It is best to dig the tubers and save them over winter to plant in the following spring.