is your tree grafted onto a rootstock? if so can you tell if the new growth is above or below the graft line? if its below the graft line it is definitely a rootstock sucker and should be removed, if it is above the graft line it is simply the start of a new low branch and cutting it off would simply be for aesthetic purposes.

As for the pot size, it seems to be a bit small for that tree but I don't think it will stop growing anytime soon, Someone with a bit more knowledge on pot sizes for citrus many be able to help more.

This post was edited by TheRiGuy on Sun, Nov 2, 14 at 1:46

Oh I never grafted it, it was a seed I planted and that was about it!

I can probably get a bigger pot but I think it will end up being difficult to take it outside during the summer days (chicago).