I am saddened to learn of this. That was a really cool tree.
Last year my stellata produced only two blossoms, and I have no idea why. I thought it might be too wet, but it was draining well. Instead of a full repot, I removed soil from the top until I got to the roots, and around the edge of the pot where it seemed like the soil had broken down. I replaced with fresh soil and hoped for the best. (I did this after the leaves had hardened.) At this moment, it is in the process of opening thirty blossoms. The only other thing I can think of is that for summer and into fall I was using an organic liquid 10-10-10 fertilizer.
When you mention ‘expensive lesson’, I am reminded that my grandfather once told me, “the school of experience is indeed the best teacher, but the tuition can be awfully expensive”.
. It is the first tree I loose and it probably wouldn’t have happened if I would have gotten it now. The flowering of magnolia is not a good indication as can be seen from mine (it had the most buds I’ve had on it. When is the last time you repotted yours?
