I have been leaving dahlias in the ground for some years, but want to lift them, split them and plant them straight back into the ground. How and when should I do that?
Q: I have been leaving dahlias in the ground for some years, but want to lift them, split them and plant them straight back into the ground. How and when should I do that?
A: With climate change and milder winters, dahlias have become almost as dependable as hardy perennials, coming up year after year when left in situ. Nowadays, I only lift one of each variety in my garden in case of long-term frost. By August the following year it’s impossible to tell which of my dahlias were lifted and which were left in the ground since they all flower equally well.
Dahlias are not hardy and need to be treated with respect when lifted. My suggestion would be to leave those plants undisturbed until spring next year. I’d wait until the new shoots are emerging or are about to emerge in April. Once you spot them, dig up your tubers.
Split them with care as the tubers are easily broken off. I use an old kitchen knife, on mine, slicing down through the dahlia crown, and then carefully removing any damaged root or tuber. Make sure each division has a shoot or bud and re-plant in well-dug ground. Protect against slugs, since newly emerging shoots are highly vulnerable.