Easy growing tips from dahlia specialist, Aylett Nurseries in London Colney
PUBLISHED: 00:00 21 July 2020
Dahlias bring colour, architectural interest and fun to summer borders
Dahlias are stars of the summer border from July to the first frosts. There’s a good range of colours from purple, orange, peach, yellow and white to deep maroon and brightest red, and flower shapes ranging from spiky cactus types, dainty pom-poms with intricate petal designs to huge dinner plate sized blooms. They make lovely cut flowers, and grow well in containers if your garden space is limited, although it’s important to choose the right sized pot for your dahlia. Some can grow quite tall and with large blooms, so a container needs to be robust enough to support the plant. Dahlias originate in the mountain regions of Guatemala and Mexico, where it is the national flower, and so plants appreciate a warm, sunny spot in the garden. But they can also grow in shade, and it’s worth experimenting with some varieties to find which ones will thrive in these conditions.
Dahlias are easy to grow and require minimal maintenance once they start growing. They grow from tubers, a thickened underground stem or rhizome, and are tender plants. Once the foliage has died down after winter frosts, there are two options to keep your tubers for the next growing year. You can leave them in the ground, mulching with garden compost or organic matter after cutting back dead foliage, or dig and lift them and store in a dry frost-free place once the tubers have dried out. If your soil stays wet or very dry over the winter, then it’s probably best to lift the tubers and store them. I have heavy clay and lift my tubers and store them, then pot up in late March to early April and put plants into a cold frame to start them off before planting in the garden in the second half of May. I keep some horticultural fleece on hand to cover young shoots when planted in the garden, should any late frosts be forecast.
Family-run Aylett Nurseries at London Colney near St Albans has a rich heritage of growing dahlias. Roger Aylett, the late founder of the nursery, adored these flowers from an early age. Roger began the nursery in the 1950s and initially grew cut flowers. Dahlias were the must-have flower, so he decided to specialise in them. Roger sold cut dahlia flowers in Covent Garden and displayed them at flower shows, including at nearby Harpenden, where he started taking orders for plants from visitors wanting to grow them in their own gardens. Aylett Nurseries soon began exhibiting at prestigious Royal Horticultural Society shows and the company went on to win dozens of medals for its displays of dahlias.
The nursery no longer shows dahlias but does celebrate this special flower annually with an autumn festival dedicated to the plant and the opening of its Dahlia Field and Celebration Garden. In light of this year’s Covid-19 restrictions, do check the nursery’s website for further details of these events as they may be postponed or cancelled.
The nursery is still recognised and known for its dahlias and produces home-grown plants for sale every year. In January, tubers are taken out of storage and laid out on moist compost in the propagation house. With constant light and heat, the tubers soon sprout new shoots which are taken as cuttings, then rooted and potted on. Around 17,000 cuttings are taken each spring, which create all the plants for sale in the nursery.
Aylett Nursery’s tips for growing dahlias:
Prepare soil first by digging in well-rotted organic matter and adding bonemeal or a general fertiliser.
Plant tubers or plants started off inside in pots once the danger of frosts has passed. Water well, and insert a bamboo cane or stake when planting (be careful not to damage the tubers with the support). Bedding dahlias don’t always need staking, unless your garden is in a windy location.
Keep weeds at bay and remove slugs and snails. Add a mulch of organic matter to maintain soil moisture and suppress weeds. ‘Stopping’ is the removal of the growing tip when about four pairs of leaves have been formed, and this creates stronger plants. Nip out the tip just above the third pair of leaves, but avoid squashing the stem.
Feeding and watering
The secret of growing successful dahlias is to feed, feed and feed. Feed every two to three weeks from August with a high potash liquid feed. And water plants regularly during the growing period.
Remove old flowers regularly to encourage further side buds to develop and flower.