Commented: What is wrong with plumeria!?!Called "Black tips"
did you protecting from frost or cold weather? If not, you get that. If plant survived this winter, new growth will emerge from side.
Commented: Rooting watering questions...Try bag rooting... it is best way to root the plumeria.
Good luck,
https://southerncaliforniaplumeriasociety.com/bag-rooting-methods/
