I planted a new Susan Magnolia earlier this Spring, courtesy of Vancouver's $10 tree sale. I did a lot of work to prep the bed ahead of time, and the tree seemingly flourished, putting out a lot of growth in its first year. In the last two weeks, since the rains made a sudden comeback, it's immediately started to struggle. The newest leaves are showing die-off and brown spots are developing on all the foliage. This doesn't look like Fall changes to me, but rather appears to be something fungal? Am I right in that assumption? Magnolias are totally new to me, so I have experience to work from on this. Thanks in advance for any advice!