When is it safe to fully unwrap a scion graft?

[Esolin]

About 3 or 4 months ago, I attempted my first grafting, placing three kishu scions on a prostrata juniper. I didn't have grafting tape, so I used teflon plumbers tape to secure/waterproof each cut, then placed a bag over the scion with a zip tie for extra pressure to make sure the cambium layers made good contact. Two of the grafts succeeded. The bags have been fully cut open in dry air for weeks now and the scions are still green and show tip extention. However the zip ties/teflon tape are still in place.

I can't seem to find any solid info online on when it's safe to fully unwrap a scion graft, perhaps because smart grafters use grafting tape that naturally rots off. Since I've never grafted before, I don't know what the time scale is. Should I cut the zip ties and unwrap now? Should I wait six months or until the start of fall? My concern is that the zip ties which kept everything immobile while the cambium layers merged, will eventually cause harm by constricting the graft points. How long does it normally take for a scion graft to become structurally sound on its own?

 

[Shibui]

Attached and structurally sound are 2 very different things. The point of graft will always be slightly weaker than any other part so always be wary of bending close to the point of graft.
My experience with juniper grafting is that they are slow so I'd be giving them 6 months if possible. Definitely keep an eye on the ties and cut them if it looks like they are getting too tight. The scions are healthy so there must be some connection through the graft but it may only be a small bridge at this stage or you may have done a really neat graft and it has all healed up all round.
Trimming the stock shoots close to the graft will help the tree concentrate more flow through the graft which will, in turn, speed up healing and growth.
If you cut away more of the plastic bags you should be able to check the callus forming at the graft junction. That will give a much better idea of how well it is healing which should also help decide when to cut the ties.
The grafting tape I use often needs to be cut off but it does stretch enough so the tree is not strangled. I usually cut grafting tape a year after the graft.

 

[Esolin]

Thanks, Shibui! Very good info. I'll trim back the plastic and stock shoots, but leave the ties and assess again in the Fall. I do plan to wire/bend them eventually--probably in the Spring, so I will be extra careful not to stress the graft joints when I do.

 

[Wires_Guy_wires]

I've had fully merged grafts fail after wiring with a years worth of growth. So my aim is two years of growth before wire even touches them. But I'm also trying to graft in directions, which seems to be working. This way I don't need to wire it until much later.

 

[Esolin]

I've had fully merged grafts fail after wiring with a years worth of growth. So my aim is two years of growth before wire even touches them.

Good to know, thanks. I'll wait two years then before wiring. I've heard kishu gets harder to bend after 3 years or so, but with a slower growing graft, I imagine I have more time. Eventually the grafts will form the apex and primary branch of a literati piece, so they will need to turn 90 degrees downward, but I don't need to bend them right at the graft point. I'll bend them higher up the kishu branch in a few years.