I posted this elsewhere, but thought here would be good too.

After recently reading kada's thread on grafting crested cacti, I came up with the idea of longitudinal grafting, i.e. cutting a section of cactus lengthwise and grafting that to a stock. I'm not sure if this is a known technique already or not, but couldn't find anything on it.

The idea is that instead of cutting laterally, as would normally be done, and thus ending up with the vascular tissue as a ring, cutting longitudinally will result in the vascular tissue being arranged in a parallel line. This then makes lining up the vascular tissue of the stock and scion much easier.

A picture borrowed from kada to show you what I mean about the vascular tissue being arranged in a parallel line (in this case on a crested cactus):




Another picture borrowed from kada, this time showing how to align the vascular tissues:




So three weeks ago I decided to give this idea a go, with a TBM pup.

This is what the scions looked like after being grafted and allowing to bond for a few days:





And so as to not waste any part of the pup, I laterally grafted the base too:




Now three weeks later, the laterally grafted base is doing well and one of the longitudinally grafted sides is beginning to pup. The other side I am doubtful will pup, as the bond between the scion and stock has slowly pulled apart, leaving a cavity almost all the way through the centre, so I'm no longer sure if there are any vascular tissues touching. The scion is still turgid, but TBMs are pretty thick skinned.





Anyway, I would call that a success and will definitely be doing some more grafts like this in the future. I would be interested to try this with seedlings too.

That's really cool. This could be a novel way to rescue cacti that have rot affecting one side of the plant.