Two Marches ago, we planted a star magnolia in our south-facing front
yard in Portland, Oregon; it bloomed profusely. Last year, it bloomed
some, but not as much as the first year. This year, the other star
magnolias on our street bloomed beautifully in March, but ours didn't
bloom at all! The leaves appear to be perfectly healthy, it just
never generated flower buds.
What would cause this? Any ideas?