I have 4 acres and lots and lots of trees. I stuffed the bottom of the pots with leaves from oak trees, and I have several pine trees that drop needles like a oak tree shedding its leaves in the Fall. So those pine needles were mixed in with all the leaves. On top of that I had some homemade compost. So this soil is rich, rich, rich.
I would say they did better because of the pot soil but where I was trying to grow them is in what was once a gravel patio outside the master bedroom. That gravel is covered with 5 ft of the same thing I am using in the pots. The only different is there is gravel in the garden giving more drainage. They were dying every winter. I have not been able to keep them alive through the winter.
I will look through my pics to show the difference of size I received and what just one season produced in the pots.