My plant needs transplanting. I'm not to sure about what size pot to use. It has been in this pot since I bought it 2 yrs ago. It was infested with aphids last winter, which I did get under control for now. When I took it out to look at the roots, it was like one giant ball of roots wrapped around the pot like hair. It's extremely tight, the root ball. It's pot size I think is too small. It's 9 1/2 pot. I have an 18-in. pot which I think is too big. Thank you for your time. It is appreciated.