What is this growing on this stem?

Can anyone tell me what has taken hold of this please, its a little variegated tree growing in a pot. I did clip it rather vigorously. I think the tree has "had it" but just curious.
Many thanks!

 

Sorry the picture is not really big enough to see what you are worried about, at least for these old eyes.

 

Any better?

 

I've got a feeling you might have something like a variegated willow there?

Anyway, not really sure what you mean by, "what is this growing on the stem"??

The large knot in the stem is the graft and the green leaved parts are coming from the rootstock and should be removed as close to the stem as possible.

Any shoots that form below that large knot in the stem need to be removed ASAP.