Your friend is right. If your orange tree is grafted on to a root stock
(which is very usual), then, yes remove the sucker growing from BELOW the
graft. The graft will usually be a swollen spot on the main stem or trunk of
the tree. I have a lemon tree that regularly grows vigorous sucker growth
that I remove. The Oranges that you will get from the root stock growth will
be poor quality.


Ozzie