How to overwinter dahlias so they keep blooming year after year

How to overwinter dahlias so they keep blooming year after year

Mastering how to overwinter dahlias will give you almost magical powers: You’ll be able to keep your dahlias alive during the cold winter months. But what are the best ways to realize this garden idea?

Well, even though it may take a little time and effort, we can promise you this: It’s 100% worth it to see those bright, bold blooms coming back year after year — and that’s no small feat, especially when you spend all that time on Learn how to deaden dahlias already.

So here’s how to get started on this clever garden trend…

How to overwinter dahlias

We know, we know: once you’ve overwintered one tender plant, you’ve surely overwintered it all?

mistake! Unlike the overwintering process of geraniums, learn how to overwinter dahlias no It involves rushing your precious flowers indoors and pampering them at the first sign of autumn. On the contrary, in fact.

Close-up of rich purple dahlias in bloom

“Dahlias and cannas can be left in place until the first signs of frost damage affect them,” Monty Don advises on his popular gardening blog.

“They can then be cut, dug up and bought indoors to inspect before being stored in old potting compost in a cool, dark place where they will survive but not grow over the winter.”

Which is… well, that’s all very well and good, but it’s a little Brevity,Monty. Fortunately, we’ve consulted a team of experts and put together a guide on how to overwinter dahlias, just for you. Because, as you’ve probably guessed, there’s more than one way to do it right.

What you will need

If you hope to overwinter your dahlias properly, you will need…

  • A good pair of scissors

  • Garden fork

  • Unheated shed or garage

  • Labels

  • Cardboard box lined with paper bag/brown paper

  • Dry sand, soil or compost

How to pot dahlias in pots

If you’ve been busy growing dahlias in pots this year, you’re in luck: These little beauties are incredibly easy to overwinter.

Dahlia in container

Dahlia in container

“Bring the pot into a dark, unheated garage or frost-free shed,” says Maurice Hankinson, director of Hobbs Grove Nurseries.

“Let the compost dry out completely over the winter, and remember that it is a good idea to reduce the top growth by about half (not to ground level).”

In the spring as temperatures rise, you should start to see some new growth from the base. This is a good time to return the plants to the light and start watering them, while continuing to work hard to protect them from late frosts.

“You may want to repot it to a larger size, or at least remove some of the old compost and replenish the pot with some new compost around the roots,” Morris says.

“This is also a good time to prune those old stems to make them tidy and you should be ready to enjoy another summer with these beautiful plants.”

How to overwinter dahlias in garden borders

How to keep dahlias blooming: A close-up of red dahlias in the New Forest, UK

How to keep dahlias blooming: A close-up of red dahlias in the New Forest, UK

If you are planting your dahlias in the garden border (or… Anywhere In your garden, to be honest), do not despair: of course, there is still a way to overwinter.

“These colorful plants overwinter from year to year through their fleshy tubers embedded in the soil,” says Morris.

“The key to successfully maintaining these plants from year to year is to preserve the tuber by protecting it from rotting or freezing.”

Ripe dahlia tubers are dug up for the winter

Ripe dahlia tubers are dug up for the winter

Wait until the dahlias’ leaves turn black due to the first frost. Next, cut off the old flowering stems about 5cm from the base (throw them into the hot compost bin when you’re done), and use a fork to pry the plants out of the soil.

Use your hands to brush the soil away from the tubers, being careful not to bruise or damage them at all, then hang the healthiest tubers upside down in a cool place to dry.

Finally, transfer your tubers to the cardboard box mentioned above, cover them with dry sand, soil or compost, then Leave them alone In your garage or shed. (Hint: It’s a good idea to label them, so the future knows what they’re dealing with.)

Dahlia flowers growing in pots and window boxes on the balcony

Dahlia flowers growing in pots and window boxes on the balcony

When spring comes, all you have to do is dig out the tubers, soak them briefly in warm water to wake them up and plant them in warm spring soil (ideally, you want the temperature to be around 15°C).

Alternatively, you can start them indoors in pots and transplant them when they are growing.

It sounds so easy, doesn’t it? We’re going to experiment, if you’re interested in joining us…

What is the best way to winter dahlias?

There are two methods when it comes to overwintering dahlias: bring your (cut) potted flowers to a garden shed, or carefully dig up the tubers, dry them, and store them in a cool, dry, dark place. Freezing during the winter months.

“A garage is a great location for this,” says Chris Bonnett, founder of “Make sure to avoid storing them in places that are too cold or too warm.”

Can I leave dahlias in pots over the winter?

With a little TLC, you can definitely leave your dahlias in pots over the winter. All you have to do is cut back the top growth by about half, and move it indoors to a cool, dry, dark place (again, a basement or garage can be used, as long as it doesn’t drop below freezing).

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