Maintenance free Versailles style planters

The original orange tree planters at the Palace of Versailles and indeed their current replacements, had removable side panels to allow for root pruning.  Most planters sold for general garden use don't have removable panels but then again most householders won't be undertaking root pruning.

Trees planted in suitable containers can last up to 20 years.   The roots will probably have filled the container after that time and replacement plants will be necessary.   For the 20 or so years before that you can enjoy just looking at the planters you have chosen.  You won't even have to paint them if you choose the right material.   The glassfibre Versailles style planters below will outlast the trees planted in them and indeed will outlast the next batch of trees.   Possibly even the batch after that!

http://www.plantcontainershop.com/versailles-style-plant-container.html

Glassfibre (GRP) Versailles planter