Last year I planted a very nice Choisya ,with lovely yellow leaves. Looking in the shrub border this morning, I note the leaves are turning green.
Our soil is very chalky. Is that the problem.
You should be able to grow this in alkaline soil. Is it in a sunny position? It may turn green if it's in too much shade.
I'd give it a weak ericaceous feed & check light levels as ceninpedr says.
I had one in shade in very fertile but alkaline soil until it was zapped by a very severe frost of -32C a few years ago. Up until then it had been growing very well, had glorious golden foliage and produced flowers too.
If your soil is chalky and free draining it is probably low in nutrients so make sure it gets fed with blood, fish and bone every spring and an occasional liquid tonic of seaweed between March and the end of June. Give it a mulch of well rotted garden compost and or horse manure in autumn once there has been some decent rain to moisten teh soil. This will help with moisture retention and improve the soil and its organisms too.
Thank you all for your advice.