Dahlias for summer colour
Now is the time to choose your favourites
Whether you have woken to a blanket of snow or just rain this morning you can cheer yourself up by thinking about your garden display this summer. I know I am itching to sow something and although I have already sown my sweet peas and have just sown some giant onions, it is too early to sow much else. But we can soon plant dahlias indoors.
Nags Hall will soon be full of summer bulbs and most of these are tender and need to be started in a greenhouse or on the windowsill, or planted in April. Lilies are the exception and they are hardy so you can plant them in the garden now or plant them in pots on the patio.
Dahlias are surely the queen of summer bulbs. If you have never grown them before I will explain how to get started below. But why should you grow dahlias?
Well, of all the summer bulbs, dahlias are the most varied and adaptable. There is a huge range of flower shapes and sizes and the plants vary from 15cm high to 1.5m. So they are suitable for pots or borders, according to which you choose. Check the heights on the packs!
The colours include almost everything you can imagine, except blue. And the taller kinds are brilliant for cutting. Unlike many summer bulbs that only produce one ‘set’ of flowers (lilies and gladioli) dahlias bloom from July to the first frost of autumn. And those with single flowers, which are now very popular, are excellent for pollinators too. Dahlias really do provide something for everyone.
Dahlias do best in a sunny spot and prefer a moist rich soil. In pots they must be well fed and watered. Taller kinds will need some support. And all are prone to attack from slugs and snails so you need to keep these horrors under control.
There are two ways to start: seeds or tubers. Seeds are a great way to produce lots of plants at little cost. But seeds are best for dwarf and single-flowered kinds and NOT for the big doubles which are not reliable from seed and will never produce such good blooms as you will get from tubers which have been selected for their perfect blooms. Seeds grow quickly and the seedlings are large and easy to look after but, unless you have a heated greenhouse do not sow till March. This will produce strong seedlings to plant out in May. Do not plant out earlier because dahlias will be killed by frost.
Although the results are variable you will find some lovely plants among your seedlings and you can save the tubers of any you really like to grow another year, Some years ago I saved seeds of a single dahlia with dark leaves and white flowers and among the batch of seedlings were the plants above and below. Both seedlings were beautiful but none of them had white flowers! That is the excitement of growing from seed – you never know exactly what you will get!
On the seed racks you should find ‘Bishop’s Children’ which is seed derived from the now famous ‘Bishop’ range of single dahlias – which is the reason for the rather strange name! These seeds will produce tall, sturdy plants, with dark leaves and single flowers in a wide range of colours.
Growing from tubers is more reliable and you can buy dahlias soon. Don’t leave it too long or the best varieties will be gone. Dahlia tubers can be planted in the ground, where they are to bloom, in late March or started into growth in pots in February. The advantage of starting them first, before you plant them out is earlier flowers and the opportunity to divide the tubers so that each tuber can produce two or three plants!
The actual tuberous roots are only there to store food and they will not actually produce shoots or plants. If any fall or break off they will not produce new plants. The shoots come from the base of the old stem which you should be able to see on the tuber.
Plant the tubers in pots with the base of this stem at about soil level. Water and keep warm and light. When shoots appear you can cut vertically through the tuber, making sure each piece has at least one shoot and, ideally a tuber (though this is not essential) and repot the sections to grow on. As the shoots grow and have two or three pairs of leaves, pinch out the growing tip. This will mean a bushier plant and the more shoots you have, the more flowers later.
Whether you have a patio or large beds to fill, try some dahlias this year. Whether you want to provide pollen and nectar for the bees or win some prizes at a flower show, grow some dahlias. And whether you want to fill your house with cut flowers or look out across window boxes filled with colour, grow some dahlias.
And if you want to learn more about dahlias and other summer bulbs I am returning at the end of February to give a presentation at Nags Hall and at Betchworth. I hope to see you there.
Check for more details later this month https://www.knightsgardencentres.com/webshop/events/