Brugmansia in a large pot
Many of my neighbors have planted theirs in the ground here in Fl. I didn't. Mine keeps losing leaves, blooming, losing leaves, blooming and losing leaves. I have a several limbs with a few leaves at the top and flowers. I see other plants in the neighborhood with more leaves. What do I do? S.Sessions
Yellowing leaves on Brugmansia are common. They will naturally shed a few leaves to be replaced by new ones.
If they are dropping many leaves this could be due to high nitrogen in your fertilizer. Cut back on the nitrogen to see if this helps.
If they drop most leaves all at once it could be due to cold temperatures, an infestation or a fungicide treatment of copper.
Here is a link to refresh you on the care requirements.