I’ve had enough of winter now. Not that it has been an especially wintery winter, more like a long protracted autumn with way too much rain and not enough frost to kill off all those garden pests. On the rare occasion the sun pokes through the thick looming cloud of grey spring feels tantalisingly close, but it’s all too fleeting. Burying my head in catalogues choosing dahlias has proven to be a great antidote to the dismal weather outdoors. Surrounded by all that colour it’s easy to transport myself to a warm, summer’s day.
Dahlias fell out of favour for quite a while. They became the preserve of allotments and show growers, they developed a reputation for being difficult to grow and were seen as old-fashioned, but all that is changing. We’re rediscovering these fabulous plants which bring a smile to people’s faces.
Most dahlias possess eight sets of chromosomes, which is unusual – most plants, like us, have two sets. These extra genes are a dream for plant breeders, hence the eye-boggling number of varieties available. Take your pick from cactus, semi-cactus, pompom, waterlily, peony and the fabulously exotic orchid forms and that’s before you’ve decided on colour. There are pretty pastels, rich jewel- like colours and vibrant yellows and reds.
Dahlias are great value plants. If you can give them an early start and keep deadheading, they’ll flower from the start of July right through to the last frosts. Many of them make fantastic cut flowers too.
Now is the best time to order your dahlia tubers, if you want the greatest choice. It’s best to buy from specialist suppliers where they will have been stored correctly, but check to see if the supplier sends out tubers or rooted cuttings. I prefer tubers as these tend to be sent out between February and March, which is important if you want to start them off early. Rooted cuttings, on the other hand, will be despatched in May for you to pot on.
How to grow
- Store the tubers somewhere cool and dry.
- If they’re in plastic bags open them so that there’s some air-flow to prevent moisture building up and causing rot.
- In early April pot up the tubers into large pots – at least 18cm in diameter, but the bigger the better. Half fill with compost, place the tuber inside and then cover with compost. They’ll need to be kept frost-free, so keep in a greenhouse, cold frame or on a window sill. Water very lightly water so that the compost is only just moist, and don’t water again until you see shoots appearing as tubers are prone to rotting.
- If you’d like to encourage your dahlias into life more quickly you can stand the pot on a heated propagator. Some dahlias like ‘Café au Lait’ are slow to get going and will benefit from this.
- Keep all you dahlia plants protected from frost until mid to late May, depending on the weather and where you live, before planting out.
- Dig a hole and fill the base with well-rotted manure or garden compost. A pile of comfrey leaves or comfrey pellets in the planting hole will encourage lots of flowers.
- Protect from slugs in the early stages, once they get going they should be fine.
- They can be prone to aphids so check the new shoots and squish, blast off with a jet of water, or spray with a fatty acid if necessary.
- Some of the larger varieties will need some staking to support them in heavy summer downpours.