From time to time you might notice some variegation has appeared on the new growth of your cactus. In this instance my Trichocereus KK339 Pachanoi clone threw out a new pup with some variegation along one of the ribs.
Therefore, if you wish to isolate the variegation and produce a pup, with even more variegation, then a good way to do this is to attempt to get one of the areoles where the variegation is, to produce a pup.
One method to achieve this would be to cut the tip off this pup to encourage it to pup again. However there would be no guarantee that it would pup from the areole where the variegation was.
Therefore grafting can be used to isolate the areole which you want, which will then encourage it to pup.
One method of grafting which can be used is Areole Grafting.
In this instance I decided not to use an areole graft, for 2 reasons.
Firstly, the variegation went most of the way alone the rib. So I had the luxury of a long length of variegation to play with.
Secondly, I wanted to try an alternative method which I hadn’t tried before. I call it a wedge graft (similar to a slab graft). The theory here was to isolate the whole rib and include a section of the vascular ring. I suppose the intention is to capture a piece of the vascular ring, similar to a slab graft so a cross section of the vascular ring on the scion overlaps the round section on the rootstock. Hence providing a better union and providing a much faster growing scion. You can read more about this theory here. Grafting Cacti Part 2
Therefore the piece on the left was to be used as the scion. As you can see, it’s the shape of a wedge. So now the rootstock needs a wedge cut out, at a similar angle, across the rootstock and through the centre of the vascular ring.
Therefore here are a few points worth noting.
Firstly, when you cut the scion to achieve the wedge, you want to do so with the intention that each cut will be the final cut. ie it won’t be trimmed. Therefore make sure your 2 cuts are nice and straight.
Secondly, when you cut the rootstock, try and make the cut so the angle is slightly less than the angle on the scion. By doing so you can then push the scion into the v in the rootstock and then hopefully get a much better contact on each side. Bare in mind, that you do want the tip of the v on the scion to contact the bottom of the v in the rootstock.
Thirdly, if you decide to try this technique, then maybe try it using a piece of scion that you’re happy to sacrifice. Just in case it doesn’t work!
Therefore, as you can see, there is a bit to consider, and also some degree of skill (or maybe luck?) involved in achieving the desired result.
Therefore the question now was, would the graft be good enough to produce a pup.
As for the wedge graft technique? It’s probably easy to question why you would bother, when an areole graft is probably a much easier way to achieve the desired result. Plus, as you can see, I probably could have gotten 3 areole grafts from the scion and produced 3 pups. However, I’d also done a few areole grafts in the past which were successful, but tended to produce narrower pups than a slab graft.
So in this case, the goal was to try and capture some of the vascular ring with the scion and hence increase the growth rate and size of the pup from the scion. Having said that though, it’s a method you’d probably only use when trying to isolate variegation (as you only want variegated areoles), otherwise a simple slab graft might possibly be much easier.
So what happened to the rest of the pup!
So now I have more variegated material to play with in the future.
So the question is, why didn’t the scion pup?
Anyway, why it didn’t pup, you can only guess! So I think I’ll just let the pups grow larger then propagate for future rootstocks. Then we’ll see if the scion can grow a pup or 2 once they are gone.
In summary. The main reason for the wedge graft was to try and capture some of the vascular ring in the scion. The motivation was, in the past I’ve found areole grafts either produce smaller pups and or slower growing pups. I tend to think slab grafts tend to produce larger, faster growing pups mainly because of the way the 2 vascular rings cross over.
Therefore in the future, I think I will trial this wedge method again. If it can be perfected, it might produce a better result!
