Updated August 20, 2022. Dahlias (Dahlia hortensis) provide their own dramatic form and color. Being native to the mountains of Mexico and Guatemala, they hibernate in moderately warm, dry winter air, then bloom in early fall after most flowers have faded. The dahlia was first written about by the Spanish explorer Francisco Hernandez in 1570. In his writings, he told of the Aztecs’ use of the dahlia as a food source, a treatment of epilepsy, and a water pipe using its hollow stem. It wasn’t until the late 1700s that the flower actually made its way to Spain. From there, it was distributed throughout Europe. Today’s dahlias have developed many forms, sizes, and colors that are delighting gardeners around the world. In 2009, FLOWER visited Mana and Jack Joyner’s Cedar Creek Dahlia Farm to learn about varieties and get tips for growing dahlias. Also see some of the beautiful varieties they shared.
Dahlia Varieties
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This bucket of dahlia blooms packs in ‘Spartacus’ (red), ‘Santa’s Helper’ (candy cane-colored), ‘Brittney James’ (bright yellowy-orange), ‘Hissy Fitz’ (yellow with serrated edges), and ‘Highlighter’ (neon yellow).
The crimson-splattered ‘Bristol Fleck’ dahlia blossom evokes the pattern of vintage speckled enamelware.
Two show-stopping ‘Brittnay Rae Joyner’ dahlias (another 2004 seedling of ADS’ Hy Clown). As Mana Joyner explains, you get many varieties of flowers from one seedpod of a particular flower.
‘Brittney James’, a 2004 seedling of ADS’ Hy Clown, is named for the daughter of friends of the Joyners and was Mana and Jack’s first hybridized dahlia that they named.
A seedling of the American Dahlia Society’s ‘Jessica Connor.’
A bee feasts on this unnamed dahlia seedling with beautiful feathery petals.
A butterfly waits while a bumble bee enjoys blossoms of ‘Camano Shadows,’ a variety of the American Dahlia Society (ADS), with pink petals that look like they’ve been dipped in paint.
When the dahlias reach about 10 inches tall, the Joyners pinch out the top tip of the plants to make them branch and "bush out." Here, Mana Joyner shows how to disbud a dahlia plant—removing some buds to make larger flowers bloom later.
As dahlia plants get taller, they need support. Each plant must be staked or grown through wire as seen here in the Joyner's beds. The Joyners prefer wire support because heavy Alabama rains mean that every blossom can need its own stake and tie.
Mana and Jack Joyner at Cedar Creek Dahlia Farm. “We cut together and we plant together,” Mana says of her and Jack’s working philosophy. For the Joyners, everyday on the farm brings that adage to life.
How to grow dahlias – the basics
Climate:
Dahlia plants are reliably hardy only in zones 8-11. In colder climates the roots should be dug up just before or immediately following the first frost. After being washed and air-dried, tubers should be stored until spring. See more about storing dahlias below. Many home gardeners treat treat the plants as annuals in colder zones.
Dahlia Colors:
Dahlias come in every color except blue. The plants do not have one of the genes required for making blue flowers. There’s a fascinating breakdown of dahlia flower chemistry and why there are no blue dahlia flowers at compoundchem.com.
Planting Dahlias:
Warm, well-drained soil is best. Wait a couple of weeks after the last frost to plant. Most growers recommend waiting until temperatures are 60° Fahrenheit to plant dahlias outside. Plant the tuber several inches deep with the eye facing up. Unless your climate is extremely warm, do not water until the tubers have sprouted.
You can start your plants indoors in pots to give them a head start on the season.
Dahlia Pests:
Get out your favorite snail bait, because snails and slugs love the new, young growth emerging from the tubers (the part of the plant that is underground and stores energy). Two of my personal organic favorites are ‘Sluggo’ and ‘Escar-Go.’
While snails and slugs are some of the most common threats to dahlias, also look out for aphids, thrips, and spider mites. In recent years, capsid bugs have become more common and will feed on dahlias.
Dahlia Blooms:
Each variety differs in size, shape, color, and bloom time. Smaller flowering varieties tend to have more blooms and bloom faster. Stakes will be necessary to support the heavier flowers. Dahlia flowers can get heavy, so as the plants get taller, they need support. Each plant must be staked or grown through wire.
When the dahlias reach about 10 inches tall, some growers pinch out the top tip of the plants to make them branch and produce more flowers. Some growers also disbud their dahlia plant—thinning them by removing some buds to encourage larger flowers on remaining buds.
Storing Dahlia Tubers:
Wait until the stem has turned black and hardened, which normally happens about two weeks after the first fall freeze. Store tubers in a cool (45–65°F), dry area. Many people store them in the basement in a box or grocery sack with some peat moss. If storing in peat moss, be sure it is not tightly packed around the tubers. The key to dahlia tuber storage is keeping them dry and making sure they have adequate air circulation.
Buying Dahlias:
When the Joyners started growing dahlias, they could be difficult to find. But, if you want “a gorgeous, big flower,” Mana says, “you have to buy a dahlia.” Now commercial outlets like Swan Island Dahlias, Brecks, and White Flower Farm sell many varieties. Floret also has an updated list of recommended dahlia sources on their site.
Here are some more helpful tips from the Joyners:
- Contact dahlia suppliers through The American Dahlia Society. Some of the members sell their flowers to interested buyers in their region.
- Visit local farmers’ markets to find a vendor in your area. Some farmers may know of flower growers nearby, though they may not have a booth or stand of their own.
- When ordering dahlias for a bouquet, make sure you specify that you want dahlias, not carnations. Florists may use the flower as a substitute if you don’t request otherwise.
