What's ruining my Magnolia Tree leaves?

[sievans]

Hi, long time watcher, but first time poster. I have an issue and sadly local garden centre advice is no what it used to be.

I recently planted my Magnolia Grandiflora tree about 3months ago in a raised bed in my north facing garden, but the tree gets full sun for most of the day. Recently the leaves have been falling - I think prematurely - looking discoloured and pretty nasty - see photo. Quite a few leaves that have not fallen are starting to look like this as well and some look like they're being eaten.

Planted it using ericaceous compost and have been watering well, plus feeding. Can anyone provide any help/advice on how to prevent further leaf loss and get them back to their natural emerald green look?

 

[DirtMechanic]

The plant thinks its fall right now. They hail from down under. At least mine does, but it is a large plant family, and ancient to boot. Its a slow grower generally, and 3 months is not long to demonstrate transplant shock. I would suggest verifiying the acidity of the soil and continue monthly weak high P rooting or starting fertilizer liquid feedings. Too wet is a problem over time.