The history of the Dahlia is as varied as the appearance of its flowers. There is some confusion over the person responsible for naming the plant. Dahlias then underwent a few name changes for some years until eventually it settled back to what we know it as today. There is no confusion, however, over the beauty of these flowers. Bold. Cheerful. Delightful.
Dahlia variabilis, belongs to the Asteraceae family. Other well known members of this family include Lettuce, Sunflower, Gerbera, Marigold, Calendula, Zinnia and Chrysanthemum. Native to Mexico, Central America and Colombia, the Dahlia was introduced to Europe in the late 18th Century. It is a plant that is particularly well documented and much information is available regarding its earliest cultivations.
Dahlia seedlings are available in the summer months in the garden centres, ready to be planted straight into your garden. These seed raised bedding varieties are treated as annuals in the frost regions of South Africa.
Dahlias are herbaceous and bushy. Their height can vary from 30cm to well over 200cm. The compact bedding varieties generally mature at a height of 30-40cm. The stems are thick and the leaves medium sized. Generally ovate in shape and serrated at the edges. Leaf colour can vary from a shiny dark green to a dull lighter green.
The flowers of the Dahlia are amazing varied. The flowers can be divided into two main types: single or double flowered. Single flowers have a characteristic open centered disc which comprises of tiny florets in the middle of the flower. Petals, which are usually oval in shape, form a single row around this disc. These flowers are usually about 10cm in diameter. The double flower types have many rows of petals surrounding the centre disc. The habit of the petals can vary which in turn alters the appearance of the flower as a whole. The most common shape of the double flowering varieties is that of a ball or globe. The flower size can range from 10-20cm in diameter.
The available colours and variations are too numerous to mention. It will suffice to say that all colours are possible except true blue.
Dahlias should be planted in a sunny location (minimum six hours of sun) that is protected from wind. They like fertile, well draining soil. Before planting, prepare the soil by adding compost or well aged manure. Despite Dahlias requiring regular watering, it is very important that their roots do not sit in water logged soil.
Once planted, allow the plant to establish and when it displays three or four pairs of leaves, pinch the terminal shoot. This will encourage side branching which will produce a bushier, sturdier plant which in turn means more blooms. This plant benefits from regular, fortnightly feeding especially whilst flowering. Removing the old and dying blooms allows for more energy towards the production of new flowers.
Dahlias are a firm favourite with slugs and snails. They are also prone to mildew type diseases. As a result it is important to allow enough space for air movement between each plant.
If planting seed varieties, they will produce tubers. If you live in a frost free zone, these tubers can be left in the ground and they will begin flowering again the following season. In frost zones, you can dig up the tubers and store them for replanting the following year.
Did you know?
The Dahlia was declared the national flower of Mexico in 1963?