I fell in love with plumerias on my first trip to Hawaii in 1985. Although associated with the islands, they are actually native to Mexico and Central and South America. They grow in beautiful fragrant clusters which are especially stunning when used in leis, bouquets, and arrangements. The pictures above are some of my collection. Seeds do not grow true to their parent, so each seedling produces a new and unique plumeria. The only way to propagate true to the original tree is to prune and root the branch. There are so many named varieties from different countries (US, Thailand, Italy, Australia), colors (rainbow, orange, red, purple, coral) and fragrances (gardenia, peach, coconut, rose) to choose from, it's easy to become addicted. Hence, you'll find popular Facebook groups such as "Beyond Plumie Addiction" and "Plumeria Addicts". For some great information on growing plumeria locally, join the Facebook group Phoenix Plumeria Growers or visit the website "Valley of the Sun Plumeria Society".
While living in Boston, I had a solitary plant which I kept on a windowsill in a downtown high-rise. It wasn't until our move to Arizona - where they thrive in the ground if provided summer sun and frost protection - that my 'collection' went from one (a Dwarf Singapore Pink) to the 90+ varieties I have now: https://www.pinterest.com/WriteOnRubee/my-updated-plumeria-collection-2016/