I am going to plant a couple of orange trees in my back yard and I am debating on whether to buy a 15 gallon tree or a 30 gallon tree. My first thought was to go with the 30 gallon but after reading online I see some people recommending going no bigger than a 15 gallon. Cost is not a huge difference ($225 vs $150) but I can plant the 15 gallon myself but the 30 gallon is more than I want to tackle so that saves me another $75 per tree to go with 15 gallon. I have seen folks saying that at 3 to 4 years the 15 gallon will pass the 30 gallon in size. That seems odd to me. What say ye? 15 or 30 gallon?