Taking dahlia cuttings…

If you wanted to increase your stock of a particular variety of dahlia, the easiest way to do it would be to divide the tuber clump in autumn after digging them up or in spring before you plant them. Another way of propagating dahlias is by taking cuttings from the tuber. Although this is more a faff, the reasons you might choose taking cuttings over dividing are; firstly, because you might not actually have a large enough clump of tubers to divide them; secondly, because you can get many many cuttings from one dahlia tuber therefore you can quickly increase your stock and thirdly as a bit of insurance, so that if anything happened to the tuber (overwatering leading to rotting etc) you have a backup stock of plants from cuttings.

My method (and there are many helpful videos of this on YouTube/Instagram etc) is to start the tubers off mid January in a tray of compost on a heat mat. I also use grow lights which I’m not sure is strictly necessary until a shoot forms but I think it helps wake the tubers up. These should start shooting within a week or two and then by mid to end of February I can start taking cuttings. The shoot below is from a Cafe au Lait tuber, and this is the stage where I takee the cutting by snipping below a pair of leaf nodes, removing the lower leaves until there is just one pair of leaves at the top which I then snip in half. I dip the cutting in rooting hormone (this is optional) and put into a covered cell tray on a heat mat. The key is to keep the cutting moist until it roots.

There is a lot of debate as to whether you should snip a bit of the tuber off when you are taking the cutting. I tend to have better results when I do it that was but you won’t then get another cutting growing from the same spot - so it depends how many cuttings you need. The cutting should start to form roots in a week or two at which point I take the cover off and let it grow on the heat mat.