all about dahliasall about dahlias

All About Dahlias

By Katie Elzer-Peters, gardening expert and writer.

There are not enough superlatives to describe the way Dahlia flowers turn into glowing orbs of color when the sun shines through the petals. Or the sheer delight of taking a garden tour and happening upon a huge dinnerplate Dahlia flower that’s as big as your head and blooming at eye level.

You know you’re at the home of a Gardener (with a capital G) when the borders and flowerbeds are filled with dahlias. The plants take a bit of effort to coax into bloom, but they’re worth it.

Dahlias Are Tubers, Not Bulbs

Dahlias grow from tubers, which are swollen underground stems. They have eyes, which develop into the stems that grow up and produce flower stalks. Another example of a tuber is a potato, to give you a visual reference. When you see potatoes sprouting in the refrigerator drawer, you’re seeing the eyes grow.

Dahlia tuber clusters look like an upside-down bouquet of sweet potatoes. At the top is the old stalk from the previous year’s growth. Tubers, which look like small sweet potatoes, tapering to a point, hang down from the stalk. The eyes are usually located at the top of the tubers, closest to the old stalk.

You can divide dahlia plants that are more than a year old by cutting apart the tuber clump. Each separated tuber needs to have an eye in order to sprout and grow when planted.

Healthy Dahlia tubersHealthy Dahlia tubers
Healthy Dahlia tubers

Growing Dahlias

There are some plants that fall into the “not difficult to grow as long as you give them what they want” category. Dahlias are not difficult to grow, given the right conditions: warm weather, at least six hours of sun per day, well-drained soil, a diet low in Nitrogen, sturdy support (for larger types), and a winter hibernation period somewhere cool, dark, and dry.

Dahlias will sometimes overwinter in the garden in zones 8 and higher, but they intensely dislike wet feet and are prone to rot. It’s better to lift and store during the cool season.

Learn More: How To Grow Dahlias

pink dahliaspink dahlias

Types of Dahlias

Dahlias, as a group of plants, are subdivided into smaller categories based on their blooms—much like roses, camellias, daffodils, and tulips.

Unless you decide to grow and show dahlias, memorizing every single classification isn’t necessary. Here are some of the more common and popular types that we offer at American Meadows:

  • Decorative Dahlias (This includes Dinner Plate Dahlias —Though not an official classification, it is frequently used to describe plants with huge blooms the size of dinner plates (between 8-10 inches in diameter). Plants are usually equally large to support such huge flowers, with some dinnerplate dahlias topping out at 5 feet tall.)
  • Anemone Dahlias
  • Single Dahlias
  • Ball Dahlias
  • Pompon Dahlias
  • Cactus Dahlias
  • Semi-Cactus Dahlias
  • Waterlily Dahlias

Learn more about the many divisions of dahlias in our guide: How To Grow Dahlias

pink dahliaspink dahlias

5 Secrets For Beautiful Dahlias

  1. Stake at the time of planting. It is a lot easier to establish a framework of stakes and/or a lattice of stakes and twine for the plants to grow through than to wrestle plants into a support structure.
  2. Give plants a head start in containers. You’ll plant dahlias outside around the same time you plant tomatoes. If that’s not until late May or early June where you live, start dahlias early by planting them in containers.
  3. Disbud to get larger flowers. Flower buds will form in groups of three. Leave the center bud on each stalk and remove the two side buds.
  4. Seal cut flowers. Dahlias make wonderful cut flowers. Snip stems in the morning when the water content of the plants is highest. When you bring flowers inside, re-cut the ends and place the stems in 2-3 inches of hot, but not quite boiling hot, water for an hour. After the hour is up, you can incorporate the stems into your flower arrangement.
  5. Dig up after the first hard frost. Dahlias will sometimes overwinter in the garden in zones 8 and higher, but they intensely dislike wet feet, and are prone to rot. It’s better to lift and store during the cool season, giving Dahlia tubers a winter hibernation period somewhere cool, dark, and dry.

Learn more in our guide: How To Grow Dahlias

All About Dahlias

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About the Author: Katie is a writer, runner, and reader, living in southern coastal North Carolina. Her favorite garden is her wildflower patch where something new is always blooming (or taking over).

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