Dahlias are a favourite amongst gardeners for their beautiful colouring and easy growth and have been a popular planting and potting choice in UK gardens over the decades.
These colourful and bright flowers are perennials and, if the plants are treated properly, you can decorate your garden year after year with their late summer blooms. But you may be wondering how to store dahlias over winter so you can enjoy these botanic beauties for another year.
If you have potted dahlias, you will find that keeping these plants protected is actually pretty easy and requires little effort.
Below we will take a look at what you need to do to make sure that your dahlia plants survive the colder months and grow again in your garden the next year.
Are Dahlias Hardy?
Although dahlias are perennials and relatively easy to care for during the warmer months, they are not particularly hardy and don’t do well with frost.
So, there are some steps you should take if you are looking to overwinter dahlias in pots, but you will find that it is definitely worth the effort and will save you money on having to buy new plants when the next spring rolls around.
How to Overwinter Dahlias in Pots?
One of the best things about growing dahlias in pots is the flexibility it offers you in terms of moving them around as the weather changes. You can move them around the garden during the summer to ensure the best blooms and easily move them into more protected areas for winter storage as the temperature drops.
Keeping your dahlias in pots means that you don’t have to dig up your dahlias and store them. Instead, you can just move the planter into a safe place that will protect the plants during a chilly winter.
In order to best ensure the health of your dahlias during freezing temperatures, you will have to try to recreate the environment which is similar to that that dahlia tubers experience in drier climates where they don’t have to deal with ground freezes.
What You Need
- Pick a suitable location to move the pots
- Frost Fleece Material
- Gardening shears
Step 1 – Select Where You Will Move Your Pots
Your first task is to decide where you will store your dahlia pots. You should move them to cool dark and dry spots such as a shed, garage, or greenhouse where they will be protected from frost and rainfall.
You can also choose to cover your pot with a frost fleece (amazon link – opens in a new tab) to help to protect it against very cold temperatures even when it is inside.
Step 2 – Cut Back Your Dahlia Plants for Overwintering
Then to get them ready for the months ahead, you should cut the dahlia stems back with your gardening shears, so the plant is down to a few inches from soil level.
Your goal is to get the plants in the right dormant state so they will be best placed to survive the cold ahead.
Step 3 – Allow Your Dahlia Pots to Dry Out a Little
Once you have decided where you are going to store your dahlia pots over winter, your next step is to allow the pot to dry out a little.
Turn the pots on their sides to facilitate the drying out process. You should not let them dry out completely, but you do not want them to be too damp. And you will not need to water them as often as you have been during the summer months.
A cup of water once a month should be sufficient for dahlias in water that are being kept undercover and indoors.
As the month passes, make sure to do regular checks on the health of the plant and check for any rotting or dead stems you need to remove to protect the rest of the plant.
Step 4 – Place Your Dahlias in Greenhouses Before the Threat of Frost has Passed
If you have been keeping your dahlia pots in a shed or garage during the winter months, as the spring approaches you can move your pots to your greenhouse or shed to give an earlier exposure to light and ensure an earlier growth.
If you don’t have access to a greenhouse or conservatory, then make sure that you wait until the final frost has passed before you move your dahlia pots back out.
Step 5 – Put Your Pots Out Again for the Summer
Once the final frost has passed you can start to place your pots out in the garden again ready for the new year’s growth. Start to rehydrate the plants if they have shrivelled, but make sure not to overwater.
You should start to see your dahlias bloom again in mid-summer, around the middle of July.
As perennial flowers, your Dahlias in pots can be stored indoors over winter to protect them from winter frost. And by following the tips we have detailed above you can ensure that the same plants can bloom in your garden the next year.
Keeping your dahlias safe and healthy overwinter doesn’t require much effort and as long as you have the right location to keep the plants cool and dry over the winter months.
It is also essential to make sure that you take the steps to start the dormancy process in the plant, cut back dying foliage, and dry out the plant sufficiently before you put the dahlias in place for overwintering.
Garden Doctor Tips
“If leaving dahlia’s outside, wrap pots in horticultural fleece to prevent them from freezing!”
“For Dahlia’s left in the ground, prune and lift in the autumn once the foliage has died back!”
“Bring Dahlia’s in before the first frost and then place them back outside after the last frost!”
“Cut Dahlia stems back to around 2-3 inches once the plant has begun to die back for the winter!”
Frequently Asked Questions
Can you leave dahlia tubers in the ground over winter?
Dahlia tubers will not survive winter in cold climates if they are left in the ground. The tubers will rot if the soil is wet and cold, and they cannot tolerate any frost. It is a better idea to dig up the tubers, clean them off, and store them in a dry place until spring.
Do you cut dahlias back for the winter?
Yes, once the foliage has died back, cut the stem back to 2-3 inches. This will help to prevent rot and keep the tuber healthy over the winter.
When should I lift my dahlias for the winter?
You can lift your dahlias anytime between October and November once all of the foliage has died back. Make sure to wait until the first light frost, as this will help to ensure that the tubers are properly dormant.
How to lift dahlias for winter?
Carefully dig up your tubers, making sure to gently brush off any excess soil. Inspect the tubers for any signs of rot or damage and discard any damaged tubers. Store the healthy tubers in a cool, dry place until you’re ready to replant them next spring.
Hi, I’m Trev and I’ve been growing things since I can remember. When I was younger, I grew up on a farm, so I have always been around plants and animals. After studying horticulture at university, I decided to start my own nursery which I have run now for 25 years. In my spare time, I run this website – which is a resource for people who want to learn more about their gardens.