Thursday, 6 November 2014

What to do about the Dahlias?

This year I bought for the first time a Dahlia plant, as part of my push to expand the ornamental aspects of my garden. The one I acquired was "Bishop of Llandaff", a Dahlia I have hankered after for a long while - bright red flowers on dark, almost black, foliage. Throughout the Summer it has flowered profusely, exceeding my expectations, so I am keen to keep it alive for next year.

Lacking personal experience on this subject I have drawn on two very different sources: "The Internet" and "What my Dad used to do"! When I was a teenager we lived in Cornwall, which is well known for its mild climate, but even there my Dad used to lift his Dahlia tubers in the Autumn rather than risk losing them to frost during the Winter. He used to store them in seed-trays (wooden in those days) lined with newspaper, in a cool spare bedroom. As I recall, he used to remove as much as possible of the soil around the tubers, and then place them upside-down in the trays. I think this allows sap to drip out and makes it less likely that disease will creep in.

The wisdom on the internet indicates that you should leave Dahlias outdoors until the first frosts of Winter kills the foliage, which is very frost-tender and will deteriorate to a brown pulp very readily when the temperature goes below zero. This year, that is going to be a bit later than normal, because our Autumn has been very mild. My plant is still flowering:

31st October

It doesn't want to stop!

My plan is to continue the time-honoured tradition and lift this plant's tubers in the same way that my Dad would have done, then store them indoors (perhaps in my garage which is contained within the main structure of my house) and see what happens. With a bit of luck I will be able to divide the plant into 3 or 4 when it starts producing buds next Spring. But that's another story...

Anyone else store Dahlia tubers over the Winter? If so, how do you do it?


  1. Well I love dalias and usually dig them up after the first frost has helped the foliage die back, then put them in a wooden box with some damp compost so they don't dry out. It's best to try and get as much of wet soil off them when you pull them up and then cut the rest of the foliage off.

  2. I used to a long time ago. I just lifted them and put the tubers in a pot with a lot of the soil (I didn't fill the pot or anything, it was just a convenient container) and put them in an unheated garage. I lifted them after the foliage died back. It worked well, but I got tired of doing it and the earwigs would eat the flowers most of the time anyway so I quit growing them.

  3. I've only grown a few dahlias over the years and the ones I have grown were inexpensive, or grown from seed, so I'm ashamed to say that I've been lazy and treated them as an annual discarding them at the end of the season. Good luck with yours, I hope you manage to overwinter it successfully.

  4. The idea is that until the frost kills the foliage the tuber continues to grow. Our plot neighbour cut the tops off his and is putting them to store now. When we had lots in a bed we covered them with straw and black polythene and left them in the ground. This now isn't a practical option as we have plants dotted about and so they will be lifted and stored,. When the tios are cut off we will place them stem side down to dry and then store in the greenhouse

  5. I live in Germany and have two dahlias in my front garden. I lift them before the first frost and cut the foliage back. Then I keep the tuber frostfree in the room where I store our potatoes, actually on top of them on dry sand.

  6. With about 50% success I normally just leave mine in the ground and hope for the best. Last year all of my ten different varieties including the bish survived but of course it was a very mild winter.
    If I am anxious to keep them, I do as Daphne and just lift them and loosely pot them and put them in my unheated greenhouse. The soil in the pot will be moist at potting and I only water the dormant plants about twice through the complete winter. They are not bone dry through the winter as is traditional I actually plunge the pots in my greenhouse soil for extra insulation in case of penetrating frosts.

  7. Thanks for this post, I have read the answers with interest. I too have wondered what the best treatment for Dahlia would be. I have lifted, stored and separated successfully, but I have had better success with just leaving them. I worry about the frost damage as I have heard this could harm the tuber however or frosts this year were the worst in years and my Dahlias are all coming up now so it appears to have had no effect. Time will tell with the flowers, won't be that long. I did learn last year that I would get a second flush of flowers if I cut back after the first pick. Keep the plant closer to the ground and less likely to flop. That will be my Dahlia experiment for this season.

  8. Great post, I too will be attempting to store dahlias this winter for the first time, they're still flowering though so haven't yet brought them in. Good luck!


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