I have a small plumeria given to me by a friend. I have it planted in a nice pot on the patio where it is in the sun all day. I water it a couple times a week. The leaves have begun dropping off. Am I giving too much water or not enough? Why am I losing leaves?
Make sure the pot and soil is draining properly. Wet, soggy soil will cause root rot.
Plumeria prefer to have a good watering and then dry slightly.
If the temperatures are above 85 degrees you will need to likely water more often.
Here is a link to refresh you on the care requirements.