Kelways Guide to Dahlias
Dahlias are an invaluable addition to the summer border as well as many varieties being suitable for patio containers and grown for cut flowers, offering a bold splash of colour throughout the summer right up until the first frosts of autumn, making for excellent value for money plants.
Thanks to the many excellent recent introductions, Dahlias offer a huge variety of colours and forms from the more dainty to the bold and showy, exotic types and are proving to be as popular as ever.
Dahlias can be grown very easily. Best grown in full sun and a moderately fertile, well-drained soil, they are best planted out once the frosts have cleared, but to get a head-start, they can be started off under cover in a frost-free location, so you can get the most from these wonderful plants.
Before planting out, incorporate a good amount of organic matter into the soil, such as well-rotted manure and a sprinkling of a good, general purpose fertilizer such as Miracle-Gro Bone Meal. If planting directly outside, wait until the frosts have cleared and ensure the tubers are plant4ed 10-15cm deep. If you want to start them off early under cover, plant them to the same depth in 3 litre pots and plant out in their final position around the end April to early May.
Some of the taller growing varieties may require staking, so make sure you leave yourself room to get in there and do this as they grow. To encourage a bushier plant, pinch out the growing tips once they reach about 40cm in height. You can even take some control over the flower size. If you want larger flowers, reduce the flowering stems to 3 to 5 per plant. For smaller flowers but more of them, allow 7-10 flowering stems per plant.
Be sure to dead-head as the flowers to go over to encourage new flowers. You can also help prolong the flowering period and strengthen the stems by removing the pairs of flowering buds that appear in the leaf axils below the terminal bud.
Dahlias may not over winter well in the garden, except in very sheltered locations. They are best lifted after the first frost, dried and stored for planting the following spring. If you prefer not tolift them and are willing to take the chance, particularly if you have large swathes of them, mulch them well in autumn under several inches of mushroom compost, remembering to clear it away in the spring once the worst frosts have cleared.
To store Dahlia tubers over winter, allow them to have one or two early frosts which tend not to be too cold and cut them back to 15cm. Lift them, knock off the excess soil and hang them for a couple of weeks to let them dry. Next, pack them away in a crate with some moist peat or sand then store them in a cool, frost free location until next spring.