By Angelina (Alexia) Demiroska, BBG volunteer writer
If you have been in a dahlia garden before, you might’ve found yourself wondering if you were a victim of false advertising. Are these flowers that look so different from each other really all dahlias? The answer is yes.
The Dahlia is native to many regions of Mexico. The Nahuatl name given to it was Acocoxochitl (roughly translating to water cane). Some suggest that dahlias were useful in Aztec agriculture, but supporting evidence for such claims is lacking.
In the early 1500s, Spanish conquistadors began arriving in Mexico and Central America to invade the land. Botanists traveling alongside the conquistadors were captivated by the beauty of dahlias. Since then, botanists have continued to selectively breed and hybridize dahlias to eventually produce the multitude of varieties we see today.
Before botanists’ selective breeding, the earlier types of dahlia were believed to be single-flowered (only one layer of petals), or peony types (around two or three layers of petals). When European botanists took over, they followed the fashion taste at the time and bred extremely top-heavy dahlias. But because they didn’t devote much care to the stem, at one time the result was a dahlia that would flop over due to the weight of its own flower. Today, we have a happier medium, with nice blooming flowers and strong stems. Dahlias in the garden are also often supported by metal or wood stakes.
Categories of Dahlias
Dahlias can have different petal shapes, number of petal layers, and flower sizes, and they are generally categorized based on those characteristics. One example is the cactus-type dahlia, which has long petals that are rolled up into pointy tubes, and whose layers of petals collectively form a sphere shape – like a prickly cactus!
Some other types include the decorative types; balls & pom pons; singles, collarettes, and anemones; orchids & peonies; waterlilies; and stellars. For a better breakdown of the types of dahlias, check out the National Dahlia Association’s Dahlia Classification. You can also find a better visual in this post, with dahlias that are all from our very own dahlia garden!
Storing Dahlia Tubers
In autumn, dahlia season ends and their tubers are stored away for the following year. In the Pacific Northwest, relatively mild winters allow for two different options of storing dahlia tubers: dig up and store away, or leave in the ground.
If you are going with the approach of digging up tubers, you would generally want to do so in October or November. After digging up the tubers, divide the tuber clumps, wash them with a spray nozzle, and lay them out to dry. Make sure that there is a growth eye on each tuber as you are dividing. Some breeders like to store 5-10 tubers in a bag with cedar shavings, and put them in containers in their garage, although that is not the only correct answer.
If that sounds like too much work for you, you could also go with the method of leaving tubers in the ground. However, using this method may lead to certain tubers rotting or freezing over the winter. To prevent that, you can put mulch over the ground to protect the tubers. This method might produce larger tuber clumps, allowing more flowers to grow, but those flowers would also be smaller in size and have weaker stems. If that is not what you’re going for, dig up the tubers in April and divide the clumps to avoid.
There isn’t an objectively “better method” between the two, so it is really up to the individual which one they go with. Here at the Bellevue Botanical Garden, the Puget Sound Dahlia Association digs up the tubers each October and stores them until spring, when they are replanted.
Come visit our dahlias in all their glory between July and September!
