Hello Elaine,

The trees in the pots are 30 gallon Foster Holly. We put rigid one gallon pots around the ball of the tree so that seasonal color could flourish without root compettion form the tree. The one gallon pot stays in place when the color is changed. The large concrete pots that the trees are in are elevated 1/2" and conceal large drains as this courtyard is 5' below the street. Thanks,

Bill

Thanks so much, they are really beautiful.