Sick Magnolia?

[Justy]

I have a magnolia (soulangia?) which I planted a year ago.  It lost all its leaves over the winter and then I had one lovely flower.  All of its leaves are now back but they are a sort of yellowy acid green colour.  The leaves themselves are healthy enough - no spots or anything.

Does anyone know what this might mean - I wondered if it was lacking something.

[Justy]

[Merry Tiller]

Is it growing in an acid soil?

[Justy]

no - neutral.  I wondered if that could be the problem but my mum had the same type at the same time and hers is doing well on neutral soil so bit confused.