Under ideal conditions, plumerias grow into large trees. It just takes several decades. You can stake the plant and pull branches so they grow upward and then trim or prune any sideways growing branches. You need to leave the ties on for several years until the branch become strong enough to support the limb.

The Eggenberger book mentions two types of Singapores, the shrubby type and the tall type. I have the shrubby type and it has grown low and horizontally for me for the 4-5 years I have had it. I have seen an approx. 10 year old singapore of this shrubby type that is about 9 feet wide and 6 feet tall.

Interesting.... are both types called Singapore Obtusa?

I am guessing I have the shrubby type also. I sort of wanted the other type, but on the other hand, perhaps the shrubby type is well suited to remain as a potted plant. I was going to set it out in the ground, but perhaps I'll be happier with it if it remains potted. (I really don't want it growing 9 feet wide!)

P.S. Not a single bloom on the one in the picture, and it was the beginning of August and I know it stays warm at Selby since it is fairly far south and on the water.

I'll have to double check in the book, but I think both referred to as obtusa. I'll try to get back to you on that. For so long I was confused as to why I was seeing these shrubby growth forms in white singapore obtusa plants, and then I stumbled upon that in the book and it explained it for me.

I'm in Tampa also. The winters here can be quite harsh on plumerias, our temperatures go to freezing and below a few times during the winter. My Plumeria in the ground is also about this height. Because during the winter they could lose the whole tree except the root ball, and what you see there is growth that happened from March to today. The Singapore Frangipani on display in Bush Gardens but they are quite tall 12 feet or so. The plant could be a dwarf singapore too.

I have 6 Singapores that are over 10 feet tall growing in large containers and are still blooming. I've seen the Singapores at the entrance to Busch Gardens. They are absolutely stunning and appear to be old trees. Exotic Plumeria sells the dwarf Singapores. The leaves are smaller and the flowers aren't as fragrant as the larger growers.