Help with magnolia

Hi
I’ve planted this magnolia tree in May.
Recently I have discovered black/brown spots on many leaves. And eventually they turn complete brown and die.
Also 2 of the buds are turning into flower but they don’t look health either.
I didnot notice any bugs/insects except odd spider.
I did add Miracle Gro all purpose continious release plant food when I first planted. And I have used mixture of ericaceous compost and existing garden soil .
We live in West sussex (BN13)

Could you have and look please ?
Thanks

 

Forgot to add photo of trunk

 

I wouldn't be too worried about the leaves, as long as its just a few, but the flower bud doen't look great.
It could just be the plant getting established.

I assume you have not let it dry out at the roots.

Trunk looks ok to me.

 

I don't think it's something to worry about. However, if you want to be prevent any future disease you could search on the internet what kind of substances you should spray it with.

 

No worries @tugrul mine is exactly the same it'll come good it seems to do it every year at this time.I'm guessing it's down to the fluctuations of temperature and it'll be losing it's leaves before long.