Dahlias are tender tubers so it is best to plant them up to start with into a container or pot that can be kept in a light position that is frost-free.
The root structures of Dahlia tubers look a bit odd, especially on more established plants, like a bunch of chipolatas that are gathered together underneath a stem. Plant the tubers with the stem at the top, into a large pot, preferably a 2 or 3 litre size, using good quality multi-purpose potting compost. Water in and then keep the compost just moist. Plant out once the risk of frost has passed in your area, usually around late May/early June.
To get the most flowers from each plant it is necessary to pinch out the tips of the main shoot down to the top pair of leaves. This will encourage a more bushy plant. It is also a good idea to allow just five/six stems to grow so that you will get strong healthy growth and an abundance of flowers. It pays to be ‘cruel to be kind’ with Dahlias and any cuttings you take off can be potted on to make new plants.
The plants should have bushy green growth by the time they are ready to be planted out into their final flowering positions, either into large pots or containers or into a sunny garden border and should be in flower by July and will continue to flower until the first frosts blacken the foliage and flowers, so depending where you live this could be mid to late October in many parts.
Dead head fading blooms regularly, cutting off the stem as well as the flower head. This helps to prolong the flowering period as well as making the plants look more attractive.
** Remember that rounded firm buds are ones still to open and the pointy often squidgy ones are spent flowers so can be removed.
Brookside Nursery Top Tip – *Pick the flowers of dahlias only when they are almost fully open as dahlia buds do not open in water and to keep them looking at their best once picked, recut the hollow stems under running water to prevent air locks.
Pests - Earwigs can be problematic when growing dahlias as they like to munch flowers and leaves, but you can take steps to lessen their impact organically by putting some straw into some small pots, turn them upside down and place onto bamboo canes and dot these around the dahlia rows or blocks. The earwigs will crawl up these instead to find shelter. You can then dispose of them far away from your precious dahlias.
Slugs too can be nuisance especially when the shoots are just coming through so sprinkle crushed egg shells or horticultural grit or place a copper ring around the base of the plants to deter them. Night patrols with a torch can be very effective if you don’t mind picking them up!
An effective option is to use an organic treatment that is safe to use around pets and wildlife.