Answer: It usually takes only 2-3 years for plumeria grown from seed to flower. If yours are getting correct exposure to sunshine and sufficient moisture to keep them healthy, the only other cause (in my experience) for non-blooming would be too much nitrogen fertilizer. If you feed your plumerias, use a fertilizer low in nitrogen and high in phosphorous and potassium (such as a 5-10-10- or 10-20-20). If they are planted close to a lawn that is regularly fed, the nitrogen from the lawn may keep them from blooming.
Best wishes with your plumeria!
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