I have a M. seiboldii in full sun. Does it like it there? I really don't think so, but it hasn't scorched. However it has in other years during droughts. I suspect your problem is a water deficit. It is amazing how much water trees can sap up at this time of year. I think the plant just needs further adaptation to the spot. Scorching has never killed my plant, or even twigs: only leaves. But I am sure it has forced a higher root to leaf ratio. That's a good thing, and I see no reason why the same wouldn't happen for you.

However if you leave it there, flowering will be delayed. I am guessing by a couple years compared to a more welcoming area. Magnolia sieboldii is said to prefer part shade, soil high in humus and not very drought tolerant. As far as transplanting, yes, spring would be best - and before bud break.

Rick

Thanks Rick, You've helped me with the site and water issues and your theory about the roots' growth makes sense. I'm glad I can leave this to next year, perhaps I won't move it but somehow! add shade to the south. The magnolia at the Arb is suffering as well, and I suspect its lack of water. Karen