How to pot up dahlias and take cuttings

How to pot up dahlias and take cuttings

I’m going to plant dahlia tubers this morning, and it’s a lovely job for a March or April morning. So here I’ve got one that we stored from last year. This is how we store our dahlias through the winter, so most of them we don’t lift actually we leave them in the garden, but the ones in pots have to get lifted and they get put into crates and covered with hessian like that.

And so I’m using a peat free compost, and you want to get a pot that holds it sort of not cramming it in but holds it quite tight so you don’t waste space basically, and then the only thing that people get confused by is how deep to plant it, and you just want to do it just below the soil surface, so it could not be easier, that’s it, dahlia tuber planted, labelled, and then this will go somewhere frost free but light, with us we put it in the polytunnel on the heated bed but if you don’t have one just put it on a window ledge and just water it every few days but not too much. So that’s that done.

Here are some that we actually planted a month ago, so they’re starting to shoot, and I just want to show you how to do a cutting from a dahlia which is a very very easy and positive thing to do because you can easily turn a tuber like that into double the number, no triple the number of plants or more, so from there that will be planted out, but I can take cuttings from it in a month just like we’ve got here. This is a dahlia called ‘Emory Paul’, which is a real whopper, and, because it’s a whopper I don’t want too many shoots left on the tuber because it puts too much strain on it and you’ll actually not get so much flower and more leaf, and so for ‘Emory Paul’ I actually only want it to form three main stems. With most varieties with smaller, well medium sized I might go for five and for small heads I might go for seven, but for ‘Emory Paul’ I just want three, and always with taking a cutting, you want to try and get a bit of tuber or stem with your cutting, and so for instance here I’m just going to try and nick into a little bit so I’ve got a bit of harder material, so you see like that, below the cutting, so that’s step 1.

Step 2 is pinching out the tip. Now what that does is it removes apical dominance, and then the plant puts energy into forming roots, not growing up and forming shoots and flowers, so you do that as the next thing, and then any leaf that would be below the compost, you remove with a knife or a pair of scissors, because otherwise that will rot, and then the final thing which I always find rather weird, but particularly with ‘Emory Paul’ which has whopper leaves, I’m actually going to cut those in half because they’ve got to photosynthesise and transpire, and this shoot has got to suck up enough water for it to do that, and by reducing the leaf surface area, I improve the chances of it rooting rather than flopping. That then goes round the outside of a pot, and I tend to use black pots for this because they absorb heat of course like a black car, you always know that when you’re on holiday, and that goes right the way around the edge, and then what happens, rather than putting it in the middle, is it’ll hit the plastic sooner than if it was in the middle, and it will absorb the warmth, so then the root will come out the bottom, hit the plastic and break, and you then get lots of lateral rootlet formation, so you get a rooted cutting forming more quickly. So I’ve got another one here, so again that one goes around the outside. And then I’m going to leave those three cuttings on the plant, but if it forms more which it probably will, I’ll go back in a week or two’s time and take them and put them into this pot, so then all I need do is label and water. So I’ll come back to these in three weeks and show you what to do once they’ve rooted. Great!