I bought my angel trumpet in October right before winter. It did great...flowering throughout the winter and early spring. Recently, (april) it is getting yellow leaves with the edges looking like they were bitten off and there hasn't been any flowers. Am I over-watering? Do I have an insect problem? Do they go through months of no flowers? We do live in Phoenix where it is rather dry so I try to keep it moist. It is in a pot on our patio that recieves filtered sun.