Like Hetty said these are trees, if the parent of the seeds are big, they will grow big too. If you grow them in big pots, they will grow fast to its mature size. I have seedlings taller than my 5 year old Plumerias. I do have seedlings that are slow grower but the varieties are dwarf or compact.
Several of my "big plumeria" seedlings are still crammed in quart pots. (I know, I know they need big pots.) But my plan is to repot them all next spring so they can take off and hopefully bloom. I can't afford for them to grow big fast, it will overwhelm our small yard.
