How To Grow Dahlia Tubers
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.
HISTORY
Native to the highlands of Mexico and Guatemala. Considered a useful edible plant in the ancient Americas for its 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!
USES
- 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 the central node when plants reach 12 inches tall to encourage branching.
PESTS/SPECIAL CONSIDERATIONS
- 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.
