I have a Sorbus 'Embley' tree which I planted about a year ago and I have
noticed that some of the leaves are going a sort of mottled yellow. It does
not look like a chlorosis problem as the leaves are not completely yellow
and they look very healthy. According to the catalogue the leaves should be
deep green. Apart from this the tree looks very healthy. It is well watered
and in well drained soil.

Could someone please advise me what the problem may be?

Many thanks

Les