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I have a tiny two ball Tephrocactus Geometricus that has done nothing for over a year.
I have no experience with grafting but seen wonderful results and have started to appreciate it.

I have an opuntias subulata, myrtillocactus geometrizan would either of these suffice? Or would you advice finding a different stock?

I am guessing myrtillo would be more suitable as it's more sturdy to physically hold up a two ball tephro.

I am thinking to graft two tiny Uebelmannia cacti onto the subulatas.

Any advice would be appreciated.

In your situation I'd choose subulata for them due to relative ties.
PS But IMHO better is to grow on own roots. In relatively big pots with good watering and fertilizers , in greenhouse they grow as on steroids.
PSPS but they may be very slow at beginning.

Agreed - before resorting to grafting (it's the wrong time of year in the northern hemisphere, anyway), see what's up with the root system. Had a poster this spring with a similar problem, he'd simply been sold a start than had hardly any roots. The solution in that case was to actually reduce the space in the pot with some rocks - see: http://www.cactiguide.com/forum/viewtop ... us#p386037

If you do decide to graft it, subulata would be most suitable, according to Craig Fry - see: https://www.cactiguide.com/forum/viewtopic.php?t=36824

Thanks for the replies. Yes I heard it maybe too late to graft in September. Someone told me to only do it during months of the year without a letter R in
The root system is quite vast actually. Everytime I think it's about to grow it's actually developing some random scars...one can be visible in the photo below
Thanks for the tip with using smaller pots or stones. A few weeks ago I repotted it using lechuza pon, it now needs watering much more frequently, strange it's using up water but not growing.


Also thanks for the links to those articles. I'll give all of the advice a try and see how I get on.

If it's filled that pot with roots, then I'd try giving it a bigger pot in the spring - the point in the link I gave was to have the volume of the pot not too much larger than the root ball, which was not well-developed on that particular cactus. This species has deep roots once it gets established, and deep pots are best then. How deep is this pot you've got it in?

Tephros seem to be prone to developing scabby patches - I've seen it on my articulatus, others have posted about the same thing on alexanderi and geometricus. Don't know what causes it, but everyone who's tried cutting it off found the tissue underneath is healthy, the damage is just superficial. I zoomed in on your picture, looks like you've got the same thing. As long as it's firm and dry it's nothing to worry about, just a bit unsightly. Could be some kind of fungus, maybe fungicide would prevent it - but once it's there, it's there. The scabs don't seem to get too large, fortunately.

Thanks Green knight. I'm so glad to hear the scabs are norma and harmless. I'll try spraying some neem oil spray or pesticide on it.

Here's a photo of the root system and the pot it was in. Ive also pictured my other geometricus which is a Tephrocactus Alexanderii var. geometricus. To be honest I thought it was just geometricus but then realised with the spines it is a different one. I'm just trying to root it at the moment as it was a cutting. I hope my other geometricus will get as big one day, at the moment the two balls are smaller than only one of the Alexanderii balls.

anttisepp wrote: ↑Wed Sep 08, 2021 7:13 pm In your situation I'd choose subulata for them due to relative ties.
PS But IMHO better is to grow on own roots. In relatively big pots with good watering and fertilizers , in greenhouse they grow as on steroids.
PSPS but they may be very slow at beginning.

That's great to hear thanks! I heard they usually grow one new ball year but I guess with time that will multiply I'll find a bigger pot for it.

It does have good roots. I think you just waited too long to repot it, and you won't see any new growth result from that until next spring. You don't want to get too carried away with the pot size, but I think one an inch larger would be good.

You could repot it this fall, after it goes dormant, then don't water until spring. This can work well, it gives plenty of time for any root damage to heal before it's watered, and it's a time you don't water anyway so there's no interruption in the growth period. That's what I did with my articulatus - I bought it in the fall bare-root, potted it up and left it alone until spring. Once it got watered, it wasn't long until I got new growth.

As for grafting, I'd suggest you first practice with less-valuable species.

Thanks, glad you agree that the roots look ok. I'll try repotting it and maybe try grafting some other cacti. I have two small Uebelmannia Flavisspina that are a bit desiccated so could do with grafting to save them, will try one first.