Is it below the graft and does it have the same leaf shape as the upper leaves? I just ask because if its low grafted it could possibly be ok. If its not the same kind of leaf and belwo the graft then it is a sucker. Its best to grab the sucker at the base and pull off the whole thing. Some people leave them if they want a interesting plant and they like it. I tend to think it takes energy from the desirable part of the plant and could possibly overtake the grafted part if its a vigorous understock(the bottom part of the tree before grafting).

Thank you for the info. How does one know if the graft is high or low. Is it defined in inches or proportions?

That is a good question and I think its relative to the particular cultivar. A high graft for a Inaba Shidare might look like 8-18 inches of straight trunk below the graft whereas a low graft might be less than 8 inches from the ground. Its hard to tell you exactly because cultivar and age of tree come into play, etc.

I think any dissectum that looks like a mop head on top of a tall stick is considered a high graft. Maybe someone can explain it better. Some cultivars such as Seiryu are grafted so low that often you can't really see them.

I'm not totally sure where the grafts are on all of my trees. On Tamukeyama, the bark looks remarkably different above a certain point. Would this be the graft?

Yea, that would be it. My Tamukeyama has green below the graft and a reddish bark above.