This condition can occur when the weather conditions are not favorable for plumeria. During winters, due to exposure to lower temperatures, the leaves sometimes turn yellow and start falling. However, the plant banks on its strong roots and stems even in harsh conditions despite being completely leafless. Another reason for the leaves to drop can be inadequate water supply. During the summer season, the flow of water should be scheduled. If the irrigation is insufficient, it may cause the plant to go into dormancy.