Are dahlias perennials?
When the first overnight frost falls, it’s time to safely store your dahlias for the winter. Dahlia tubers aren’t perennial; they can’t survive in frost and will freeze and die. If the ground is too wet, they can also rot and go mouldy.
If you want to enjoy your beautiful display of dahlias next year, follow the steps below for overwintering dahlias:
- Cut off the plant stem, leaving 30 centimetres protruding above the soil. You can use the stem to grasp the plant when you pull the tuber out. Keeping your fork in an upright position, dig into the ground around the tuber about 30 centimetres from the stem then carefully remove the tuber from the ground.
- Write out labels for the tubers. I always include the colour and height (tall, medium or short) on my labels so that I can dive straight into planting next year.
- Leave the tubers to rest for a few hours in a covered location with the stem pointing downwards so that any water can run off.
- Knock any loose soil off the tubers and use an old washing-up brush or paintbrush to carefully remove any remaining residues. You can also trim off any excess hair roots at this point.
- Before you put your tubers away for the winter, inspect them all carefully. Do they still look healthy? Or have they been eaten or are there signs of partial rot or an unusual surface texture? If so, it’s better to throw them away.
- Cut the stems down short; this will make the tubers easier to store and prevent mould.
- Store the tubers in a wooden box or a crate with holes. Ventilation is important, but the tubers shouldn’t be exposed to draughts, as that will dry them out. Everyone has their own method for this step: Some like to keep their tubers in dry sand or old compost, while others layer them in wood wool or straw or roll them up in newspaper. Choose the method that suits you best. Place your containers in a protected and cool but frost-free location. A basement is perfect as long as it isn’t too damp. Ideally, tubers should be stored between 6 and 9 degrees Celsius.
It takes a little effort, but your hard work will pay off next year when your garden is blooming with your beautiful dahlia perennials once again.
You can also overwinter your dahlias in pots. It’s best to keep the pots in a covered location so that the tubers don’t get wet. Your overwintering spot should also be frost-free. When the weather starts to warm up again in spring, you’ll see the first signs of new growth. You can then use a sharp knife to split the tubers and plant them back out in the ground.
Overwintering dahlias in the ground
If all of that sounds like a little too much effort, you can opt to take a risk and leave your dahlias in the ground for winter. If the winter isn’t too harsh, and depending on the location and type of soil, they may survive. Protect them with an extra ‘blanket’ of compost or straw to keep them warm. If the winter does kill them off, you can order new dahlia tubers in our dahlia shop.
The benefits of storing dahlia tubers
There is one other major benefit to removing your dahlias from the ground each year. By storing dahlia tubers, you can rearrange them each season and add new colours and varieties – to bring your garden up to date with the latest colour trends or just to reflect what you like that year. One year you can have a happy colourful garden with yellow dahlias and orange dahlias, the next year you can make a romantic garden with red dahlias, pink dahlias and white dahlias.
We have lots of favourite combinations for gardens. The pink dinnerplate dahlia Belle of Barmera looks stunning alongside the smaller Sylvia dahlia. The Belle of Barmera is a large, pink variety that goes perfectly with the orange Sylvia ball dahlia.