Cuttings - species wich don't root

[Brunãozinho]

I think it would be useful to know the experience of other growers about this.

In many cases we graft a cactus planning on degrafting it later and then rooting it. It's a great way to accelerate growth, but with a saguaro for example, I doubt it would even root at all.

So, are there other species where rooting is so hard that you shouldn't even bother about grafting them?

[CactusFanDan]

Aztekium ritteri is a very difficult one to root from a cutting. I only know of one case of this which has been successful. Uebelmannia gummifera is also apparently impossible to root, due to the gum channels.

[Brunãozinho]

Oh, good to know about that.
You got me with the gum channel thing, Dan. I have just read about it to know what it is, I found a picture of a cross section showing the gum inside the plant.
But how does that affect the roots from growing if the plant is cut?

[CactusFanDan]

As far as I can tell the plant needs the gum channels to be sealed to live, but I don't know why. However I can tell you that if the channels are cut then the gum is pushed out and dries to become rock solid.

[Brunãozinho]

It's curious that this plant has this.
But maybe roots can grow directly from the vascular rings after it is cut. I don't know if the gum channels would be on their way if that happened.

[CactusFanDan]

I think it could also be that the species isn't really adapted for very prolonged periods of drought and maybe the gum acts are an extra store of water. I'm not sure, but it would be interesting to investigate.

[Brunãozinho]

Well, in some years, if I ever get seeds of this plant, I'll try to graft and root them and come back here to write about it.

[KittieKAT]

I heard lep. Schotii are really hard to root, they usually grow like one root every couple of years
According to what I've witnessed, i have two of them and they have the smallest roots ever.