Lemonade

[FMurtz]

Should I leave a shoot from the rootstock below the graft? presumably some sort of lemon

[David E. Ross]

At the position of the graft, the tree is somewhat weak. It is not s structural weakness but a growth weakness. Nutrients going up from the roots and down from the leaves slow at that point. This does not affect the shoot from the rootstock, which will eventually dominate the plant. In the end, the grafted top might wither and die.

[Bob Hobden]

No, certainly not. It will be stronger than the grafted top you want and eventually dominate the plant. Cut it off as near the trunk as possible.

[David E. Ross]

Sometimes, cutting away a sucker is not successful. A new shoot quickly arises from the stub. If possible, pull the sucker out of the trunk or root from which it sprouted.

[penmart01]

Exactly... catch those suckers early before they grow larger, and with a gloved hand yank them laterally, on trunks yank downward. If cut suckers will grow back in the same spot only larger and often in multiples. Sometimes a sucker will persist and still grow back, then excising some of the surrounding wood and cutting deep is necessary, like removing a cancer, especially occurs at ground level on fruit trees where the sucker cannot be yanked downward. With persistant suckers on my plum trees I drill a 1/2" diameter hole 3/4" deep and fill it with caulking compound.