The secret to success with plumeria is bright light and lots of water during the growing season of spring to autumn and very little water in winter.  If you grow this plant as a houseplant you may not be able to give it enough sunlight unless you have a conservatory. Are you growing it indoors our out? Do you live in a sunny climate? This tropical plant also needs a warm home with night temps always above 50 degrees. It is a challenge for most people to get plumeria to flower unless you live in a tropical climate. But part of the fun of gardening is the challenge. Try this trick: Repot the plumeria into fresh potting soil with some Osmocote mixed into the soil. Use a container just one size larger that the one it is in now. The shock of the transplant will sometimes shock the fella into flowering. It needs repotting every 2 to 3 years anyway so Groot is due for a bigger home. Keep growing, Marianne Binetti