For general maintenance, if you wish, Choisya can be pruned after flowering. Remove the top 20 cms of growth to keep in shape and to size.
What if the Choisya has become too large? Also, sometimes Choisya can lack growth becoming bare at the bottom of the plant, leggy and the leaves yellowing despite feeding.
In the image below the Choisya, which has been growing in the same spot for many years and mostly looking good, is looking a bit tired. To rejuvenate Choisya can be hard pruned, in a similar way to Rhododendrons, cutting hard into the wood and really be quite savage. It will grow back and be healthier with new glossy foliage, although it may take a season or two. The middle image shows cutting back the Choisya, low down to the ground. The final images show the Choisya after cutting back, it looks quite denuded but it will grow back, and better.