And here is the big pereskiopsis  graft of the previus post exacly 3 weeks before

Update on pereskiopsis-opuntia grafts

Here is the pereskiopsis on opuntia ficus indiga graft posted three weeks ago

Pereskiopsis is fast enought by itself. It seems that this improves if grafted on opuntia ficus indiga. After some slow grow initialy it the grafted scion surpasses by far one that is on its own roots. The following picture is of a 1 and a half month old graft

After weeks of experimentation I managed some grafting on opuntia - ficus indiga rootstock. It seems that the trick is to put a lot of weight. A solution of 500 mg/lt ( 500 ppm ) seems to speed up  unification proccess a lot.
This is a very hard grafto of a trichocereus piece on opuntia stock I used petroleum gelly on the edges to help the graft maintain humidity during the healing proccess :

Here is another tricky graft . A Selenicereus grandiflorus slice on opuntia :

I have applied a mixture of lanolin paste and Forchlorfenuron about 3% to force the budding on the scion

Here is some of my other grafts:
Myrtilocactus geometrizans on selecinereus grandiflorus 

stenocereus gummosus on pereskiopsis spathulata

stenocereus gummosus on pereskiopsis spathulata no 2

The stock I use for grafting is either pereskiopsis spathulata or selenicereus grandiflorus. These I had to order them outside of Greece. The only cactus you can find in the wild here is opuntia ficus indica, and after many experiments I came to the conclusion that is very hard to graft. I have only succedded with very few scions. The only that is easily take is  pereskiopsis spathulata:

The same graft 3 month later, at the peak of growing season. The growth is enormous. This is after I applied a paste made of lanolin and gibberellic acid (powedered form) to the top tip of the cactus. Using this paste a managed to speed up growth of another trichocereus hybrid to 30 cm in 3 months with three applications of the paste. This one is with only one application