There are few better plants than dahlias to give a dazzling display of colour in the summer and autumn and there is no better time than now, March, to get them started.
Dahlias grow from tubers – big, fat, fleshy roots which store energy to launch the plant into growth the minute the warmth of the sun increases as the year turns.
Originating in Mexico, dahlias are sun lovers. They can be hungry when they start producing flowers and they need to be watered but not to stand in water.
Sarah Beattie
Slugs and snails love them but don’t be put off – they are easy and reward you well for the effort you invest.
Planting tips
Pick good firm, heavy tubers. Anything soft or squishy will rot. If it’s just a little patch, cut that away with a sharp clean knife before planting your tuber in multi-purpose peat-free compost.
I usually add a handful of frasse de scarabée (an organic feed made from dung beetle droppings – a start up in Nantes processes food waste through the beetles to produce an inoffensive excellent soil improver you can use in containers – no nasty whiffs of chicken poo on your terrace!) or other pelleted organic fertiliser.
Do not plant too deep – you should be able to spot where last year’s stem was cut – place that just above the soil level.
Water and keep in a light, frost-free area with a bit of warmth if possible. Your tubers will quickly start sprouting, if they haven’t already.
People who grow to exhibit will always take cuttings and even if you are not expecting to put any of your blooms on the show bench, it is worth doing a few cuttings to double (or triple) the number of plants you have for virtually no extra cost.
Sarah Beattie
When the shoots are pencil thick and about 8cm long, using a sharp, clean knife, slice them off from the tuber with a little of the brown outer covering.
Pot each cutting up in a small pot of multipurpose peat-free compost, water and put in a propagator (this can be an improvised clean storage box with a lid, the plastic containers supermarket pastries come in or a an actual propagator from a garden centre – anything as long as you can maintain a fairly humid atmosphere around the cutting).
The cuttings will soon root and when you spot roots coming out of the base of the pot, transplant it into a slightly larger pot.
I discovered – after an accident when transplanting a large dahlia which refused to come out of its pot – that a large broken stem, placed in water will eventually root and can also be planted out. Change the water frequently to avoid rot and trim neatly below a leaf joint.
Dahlias come in all shapes, sizes and shades
They can be subtle shades of cream or in your face bonkers combinations of bright oranges and shocking pink. You could even choose ‘black’ or white.
Sarah Beattie
You can have very simple pared back star shapes, almost austere in dark purple, or firework explosions of colour. Pompoms and cactus-flowered, anemone and waterlily, dinner plate to penny sized, there are so many dahlias to consider.
And even if you are feeling overwhelmed by the choice of colour and form, you must also consider size: there are ‘tree’ dahlias and dwarf dahlias and everything in between.
If you have an exposed site that is rather breezy, unless you are planting something behind them, go for a variety that only grows knee-high.
Taller dahlias should be staked. Use a stout stick and drive it into the ground before planting your pot-grown dahlia next to it – this way you avoid damaging your tubers. The large headed dahlias will need multiple supports.
Dahlias do well in containers and raised beds as long as you remember to feed during the flowering season.
Deadhead frequently to increase flowering. If you do this, you won’t mistake buds for spent flowers. If you miss one, just remember, buds are round but flowers which are spent are elongated.
Sarah Beattie
After the frosts have killed the top growth of dahlias in November or December, you can lift and store the tubers – carefully dig them up, making sure you don’t sink a fork into the tubers. Clean off the soil and store when the outside has dried off a little.
One year I diligently did this with all my dahlias, wrapping them in newspaper and layering them in stacked wooden fruit crates in the barn. The following March, when I went to replant them, I discovered most had been completely eaten by rodents. If you suspect you might have a similar problem, leave the potted ones in their pots, just move them under cover to dry off.
The ones in the ground can be left where they are and covered in a thick mulch unless you live somewhere very cold or wet over winter when lifting and storing in the house or in a hessian sack hung from a rafter are the best options.
Where to shop
Tubers usually appear in shops – supermarkets, diy stores, garden centres and nurseries – from around the end of January. If you cannot see anything you like, go online.
The big Dutch suppliers like Farmer Gracy and Dahlia Store send to France and plenty of French based nurseries have good selections.
My favourites include the magnificent D. Café au Lait, fiery D. Orange Sunrise and deep D. Arabian Night. I like the Dandy range in their happy mix of colours but then, that’s what our grandchildren call my husband.
