GET GROWING: Dazzling Dahlia Varieties

GET GROWING: Dazzling Dahlia Varieties

There are several good reasons to plant dahlias. One is the astonishing number of dahlia varieties and cultivars available to the home gardener. According to the American Dahlia Society (ADS), selection is the first step to consider when planting these gorgeous flowers.

The ADS lists nearly 11,000 cultivars and classifies these dahlias in three ways: by flower size, shape, and color.

Dahlia flower sizes are sorted into six categories, ranging from very large (larger than 10 inches—often referred to as a dahlia) to small (4-6 inches) to very small (2 inches or less). Dahlia plant height has no effect on flower size.

For most dahlias, it takes about 90 days from planting to flowering. Dahlias with the largest flowers can take up to 120 days, while dahlias with smaller flowers can bloom in 70 days.

For dahlias, small are good. More than a quarter of the 11,000 dahlia cultivars carry a BB (small) rating for flowers in the 4-6 inch range. Within this size group there is much more to choose from in terms of shape and color in the different dahlia cultivars than in other size groups.

One dahlia in this collection was introduced by Lee Bowen of Sequim. ‘Zookeeper’s Giraffe’ is a small, informal ornamental dahlia in a variegated color pattern. You can see this particular variety in the terrace garden at Cary Blake Community Park.

Another feature of mini dahlias is the different and sometimes subtle variations in flower colours. Many of them that have more than one color can be more attractive than larger, similarly colored dahlias.

There are 17 different shapes of dahlia flower. Shape mostly refers to the shape and arrangement of petals on a flower. Six of these forms—formal ornamental, informal ornamental, upright cactus, semi-cactus, curved cactus, and lacinae—almost always have a size definition as part of their definition.

Most of the other eleven figures are all smaller than four inches. Water lilies and dahlias are two such shapes that many find particularly attractive.

To learn what different dahlia shapes look like, search “dahlia shapes and sizes” online. Most of these forms will be on display by mid-August in the dahlia bed in the Master Gardeners’ demonstration garden at 2711 Woodcock Road in Sequim.

There are 15 different colours, 10 of which refer to specific colours. The other five indicate different ways in which flowers can appear more than one color. About a third of dahlia varieties have more than one color in the flower.

Here’s an interesting fact, the ads list twenty different types of dahlias with the word “blue” in their names. But none of them are blue, because there are no blue dahlias.

Dahlias are all about variety. Just when they begin to emerge after other summer flowers have lost their magic, dahlias liven up our yards and gardens with flowers that delight us in so many ways.

To learn more about varieties, selection and cultivation be sure to take a look at the ADS website located at

Gary McLaughlin is a WSU Certified Master Gardener. He is the dahlia garden area manager at the Master Gardener’s Woodcock Demonstration Garden.

Photo by Sandy Cortez/Dahlias with the largest flowers can take up to 120 days, while the smallest flowers can bloom in 70 days.

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