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The dahlia is one of the easiest to grow and delightful flowers and there are many different colours, sizes and shapes.
Dahlias grow from tubers and are purchased this way rather than by seed. The seed can be interesting to grow because the flowers will not be true to the parent. There may be a stunningly beautiful bloom, or a plant with shaggy, dull blooms on it. However, it is exciting to grow them from seed just to see what eventuates.
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Growing Dahlias – Seed or Tuber?
Plants grown from seed will flower in three to four months and they also make small tubers from which the plant will grow true to type next year. Seed should be sown in the spring or summer in temperate regions. It will take around two weeks to germinate and the seed pots should be kept moist during this time.
Growing for tubers is the only way to ensure the dahlia will throw blooms true to the parent plant – or to what is pictured on the packet. Dahlia tubers usually become available in the spring. When buying dahlia tubers, make sure they are fresh stock; they should be firm to the touch with no sign of sprouting. They will still grow if bought with a little sprout on the end, but they may not do as well.
Preparing the Soil for Dahlias
Dahlias are quite hardy growers and will grow in nearly any soil, but of course, a deep friable loam that is well-drained will enhance the growth and blooms. Too much animal manure will give lots of green growth but not many flowers. The soil should not be wet or boggy as the tubers could rot. Dig it up thoroughly and add organic compost, especially if it is sandy soil. However, do not use lawn clippings that are still green.
Plant the tubers with the necks or shoots just showing. The roots will be covered by about 10cm of soil. Dahlias will often grow and bloom when the tuber is left in a ditch at the side of the garden, but this is not ideal for them. Add some general fertiliser when the plants are around 30 cm (12 ins) tall, rake it in and water it thoroughly.
Caring for Dahlia Plants
Most dahlias will need to be staked as they grow fairly tall and have heavy blooms that weigh the stalk down especially when wet. Snails and slugs love the fresh shoots so protect them from such pests when they are young. They should be watered regularly in dry areas, but if reasonable rain falls during summer and autumn, no more water needs to be added.
When the dahlias are blooming deadhead them regularly to extend the flowering period. Once they have finished, let the plant die off completely before lifting the tubers. These can then be stored under a tree or in the garden shed during the winter. If your winters are mild the tubers can be left in the ground, but be sure you don’t forget where they are and cut them in half with the spade. Next spring the tubers can be divided before planting.
Different Types of Dahlias
There are many different varieties of dahlia and all are simply gorgeous. The large varieties are as follows:
- Decorative: these have large double blooms of 15-25 cm across. They grow up to 2 meters high.
- Hybrid Cactus: the petals are narrow and curved and not as big around as the decorative dahlia. The plant grows to 1 ½ metres high.
- Charm Dahlia: grows up to 1.2 meters and has smaller blooms than the cactus variety.
There are also many smaller dahlias variously named dwarf, pompone, collarette and water lily. Some have double blooms; others have semi-doubles while still others look like pompoms or daisies. The smaller varieties do not need staking and often can be grown from seed. They grow 40-60cm high and are covered with flowers. They are ideal for massed displays or for growing in containers.
Diseases of Dahlias
While dahlias are generally quite hardy, lots of humid weather may see an outbreak of fungal disease such as powdery mildew affect them. If it is widespread, this can be treated with an appropriate spray. If only a few leaves seem to be affected, simply snip them off and tie them into a plastic bag before disposing of them. Never place diseased leaves in the compost bin.
How to Treat Cut Dahlia Flowers
Dahlias are stunning additions to any bouquet, and with proper care, they can grace your home for a week or more. To ensure their longevity, it’s crucial to prepare them correctly. Begin by scalding the freshly cut ends of each stem in boiling water for about 30 seconds. This seals the cut and prevents sap from blocking the stem and hindering water uptake.
After scalding, immediately plunge the stems into a bucket of lukewarm water for at least two hours. This rehydrates the flowers and allows them to absorb maximum water, maximising their vase life. By following these simple steps, you can enjoy the vibrant beauty of your Dahlia blooms for days to come.
Image Credit: Deposit Photos
