Design:

The plant remaining in the orange tree box is more fragile than a plant in the ground. It therefore requires special care.

The true orangery planter box must have 4 removable sides.

Why?

Over time, the plant will develop its root system in search of nutrients, and this beyond a certain threshold to the detriment of the tree itself. The plant weakens; it then becomes essential to prune the roots and provide new soil. Removing the plant from the planter box is often difficult. The 4 removable sides make the operation easier.