I know this seems like an incredible detailed ‘how to’ simply for dahlia cuttings, but there is a reason. If you crack the skill of successful cutting taking, the world is your absolute oyster. Dahlias are nice and easy, so worth using as a bit of practice.

You must not tell anyone, but the devastating news that the David Austin rose ‘Jude the Obscure’ has been retired (for which, read discontinued) means that I am honing my cutting taking skills in preparation for the rather more tricky rose cutting season in May.

As well as roses, I am eying a rather nice rosemary and my favourite hydrangea. If you have salvias, now would be a good time. I over-wintered a S. uliginosa and as soon as it puts on a bit of growth, I’ll be pinching bits off.

Now is the time. The air is (somewhat imperceptibly) warming up and I am determined to quadruple my dahlia collection. I am not entirely sure why because I already had too many, but I have been informed by a reliable source that dahlias grown from cuttings (as opposed to tubers) are invigorated and grow true to form. Many of my dahlias have been looking a little lacklustre in the last year or so and if there’s one thing I cannot abide, it is a too-pale Café au Lait. You may think that there are greater problems in the word, and there are undoubtably are, but one has to draw a line somewhere. This is where I draw mine. 

I want frothy, crazy, photogenic, heart-stopping, rainbows of dahlias. Think Charlie McCormick’s prize-winning blooms. Ok, maybe not rainbows; my palette is too narrow for that and any highlighter-yellow or Cadbury purple will go straight into the compost heap. But I do want my muddy-coloured dahlias to be properly muddy. Last year’s tubers are having their toes tucked in compost and introduced to some gentle heat. I know it is time, because the eyes have already sensed the spring and are started to tentatively emerge from hibernation. A growing eye is a shoot, and a growing shoot is fair game for becoming a cutting. 

Here's how:

ONE:

Either buy a dahlia tuber or fish one out of storage. Late February is probably a good time to check them over anyway. Any mouldy or rotten ones, get them out sharpish before they spread to all the others. 

TWO

 Put a little compost in the bottom of a short-sided pot. If you were planting this up to grow from a tuber, you would be filling it to the neck of the tuber, but for cuttings, you want all the eyes above the compost line. Eyes (the tiny buds that grow into shoots and then stems) can be hard to see so hedge your bets and just be a bit scant with the compost. 

THREE

Put it somewhere warm. I am going big on the tuber-warming this year so I will finally get round to turning the heat mat on in the greenhouse, but that really isn’t the only way of doing this. The kitchen windowsill, on top of the storage heater, next to a radiator or just next to the Aga is good enough. 

Now you wait. If the shoot is looking pale or leggy, you are going to have to prioritise light over heat, so move it closer to a window. You need to get the shoot to about four inches tall, but don’t try and rush it to get there; the shoot needs to be strong and green. The next bit is contentious. Some cut, some pull. I am in the ‘cut’ camp.

FOUR

Fill a few pots with gritty compost. I used the last bit of a bag of vermiculite. Cuttings never like to be left hanging around.

Get the sharpest knife you can find. You want to cut the shoot at the base so you get a tiny sliver of tuber with it. Apparently if you pull it, it works just as well but the whole idea makes me wince, so I stick with cutting. Let me know if you try it.

Five

Now you have a cutting, trim the larger of the leaves, dib a hole in the compost with a pencil (dib holes round the edge of the pot if you are doing multiple cuttings at once), and pop it in. Gently firm the compost around the cutting but don’t press down too hard. Water, preferably from below, but don’t let it sit in water. Now is the time for warmth but not direct sunlight. Think gentle recovery and growth.

 Now, the amazing thing about this is that you can get a lot of cuttings from one tuber, and that means a lot of flowers come late summer. If you don’t have enough tubers of your own to haul nervously out of storage (everyone always loses some, don’t take it personally), I hear a rumour that Sarah Raven has a sale on and Halls of Heddon are selling off what they call their ‘pot tubers’ which are intended for cuttings.

I will be doing mine this weekend, but I will also be going wild and sowing some seeds that I saved from a dinnerplate, Bryn Terfel, last year. Philippa and I talked about this in our interview; we had both heard Erin of Floret say that you can expect 90% of your seedlings to be dreadful, but Philippa says her success rate is significantly more than that, so I am ready to roll the dice, and hopefully discover the new Senior’s Hope.

If you are still to source your dahlia tubers, I list my (and Philippa’s) old and new favourite varieties here.