The light of Dahlias
Back in fashion, these flowerfest plants never fail to brighten a garden
THE beautiful spell of weather recently will have enticed many of us outdoors to examine the garden.
None of our plots look at their best right now so we really appreciate bursts of colour from yellow daffs and the purple and orange crocus.
Colour lifts the spirits and it’s what most of us want from our outdoor spaces.
One plant that will deliver this in spades from midsummer to late autumn is the dahlia – and March is the month to coax those tubers into life or start growing them from seed.
For a while, dahlias were drifting out of fashion but they are undergoing a renaissance as gardeners appreciate the variety of shapes, sizes and their long-flowering ability.
Deadhead them and they will keep popping out flowers – and in some milder areas they may be the last flower standing in December.
They make superb cut flowers, enjoying a good vase life, and cutting will also stimulate further growth. However, novice gardeners may be put off by technical talk of lifting and storing tubers in the winter and believe dahlias to be difficult. Not true.
The key to growing dahlias is understanding they originate in Mexico which makes them sun lovers and unable to withstand frost.
This means you don’t plant them out until after frost has gone, which can be anywhere from mid-May to early June depending on your location.
And then you need to get them out of the ground for winter, unless you are somewhere mild and they will survive under a nice warm blanket of mulch.
Dahlias can be grown from tubers or seed. Seed is a much cheaper way – for a couple of quid you’ll get a
packet of seeds which will give you maybe 25 or more plants whereas one tuber alone can cost the same.
If you want to grow an exact variety, tubers are the way to go as seeds give variable results – but this can be part of the fun too.
Surface sow seed in a seed tray and sieve a light dusting of compost or vermiculite on top and water in. Keep in a light warm place and after germination, when seedlings are large enough to handle, you can pot them singly into three-inch pots.
Tubers can be potted now in damp compost and kept in a light, frost-free place such as a greenhouse, cold frame or windowsill. When you’re ready to plant dahlias outside, choose a sunny position for maximum flowering.
Adding well-rotted manure or compost to the planting hole will help with fertility and drainage. But if your soil is very heavy clay, you could pop some horticultural grit at
the bottom of the hole as well.
Your tuber will have produced lots of shoots at this stage, but it’s a good idea to nip out a few and leave just five – it will make the plant bushier and stronger.
You will need stakes for some of the taller and heavier varieties so it’s a good idea to install them at the same time as planting and then you can tie in the dahlias as they grow. Keep them watered while they establish and use a high potash feed while they grow, such
as a tomato feed, to encourage flower production.
As flowers finish, deadhead them but be careful not to take off new buds when doing this as it’s easy to get mixed up – new buds are round in shape, seed heads are conical.
Dinner plate blowsy varieties like ‘Cafe au Lait’ are in vogue now – this is a florists’ dream with delicious coffee cream petals with a blush of pink.
Classic tight pompons such as ‘Franz Kafka’, with its perfect curved, deep pink petals, are lollipop and fun.
Pollinators prefer the simple single flowers with an easy route to the nectar – these include any of the Bishop series with that wonderful deep dark foliage as well.
Or maybe it’s the retro cactus type that catch your eye, such as ‘Alfred Grille’, with its fiery salmon pink and orange spiky blooms. There’s a dahlia to please everyone.