Preparing dahlias for winter

Date Posted: 09 November 2017

This blog is written by an average amateur gardener. This means that I do not necessarily have all the answers and what I say should not be taken as read. The information given in this blog should not be interpreted as advice as in essence it represents the musings of a gardener about some of the issues faced in dealing with the problems and opportunities encountered throughout the seasons. The joy of gardening is what this blog is all about.

The advantage I do have is that I have the advice of my very professional gardener Gary, so Gary the Gardener’s thoughts will very much form part of what I write.

Right now my dahlias are fading fast and however much I prune off the dead heads and some of the stems I know that they are on a downward spiral as the colder weather begins to bite. So the question is what am I going to do with them?

On the South coast where I live the relatively warm wind off the sea tends to keep soil temperatures up - until of course the wind turns to the North and frost, and very occasionally snow, starts to lower the warmth of the soil. A few days of cold weather is OK if I have left the tubers in the ground but if we get a really cold spell and the ground freezes the plants are unlikely to survive. So if I am going to leave them in the ground I shall cut them down to a few inches above the soil and then cover the whole plant with a thick dry layer of mulch or other organic matter.

Or do I lift them and store them? This also carries some risk as not all the tubers will survive unless I have carefully prepared them for winter. This involves cutting the stems down to a few inches from the base and carefully lifting the plant and tubers not forgetting to label each plant with colour and name if known. Loose soil needs to be removed by hand and then they can be left, upside down, to dry off for a short while. Once they are dry they can put into trays and covered with soil or sand and stored in a frost free area to over winter. The risk is of course that some may not survive even this careful treatment.

My choice is to lift and store over winter but the choice is yours. Gary says leave them in the ground but mulch well.