well in my opinion- and it is just that, you could try banana trees, they have lots of babies so they kind of clump together, that would look great around pools- if you want to think shrubs- I would look into chaya plant. People often use that as privacy fence. It is also known as the mayan miracle plant- if you google it. The bananas could get pretty beat up if not near something for the wind- as I found out. Those are my thoughts- I am sure there are lots of ideas out there though. sagos get pretty big and look good too- I got baby ones last spring for $5 each and they have doubled in size already. hope that helps

You're in zone 9 so an assortment of tropical trees would all look good. Just watch for litter next to a pool.