Oriental Raisin Tree!!!

"Medicially, the part of the Hovenia Dulcis plant that is used is either the fruit or the peduncles (stem of which holds the flowers), and the peduncles have been reported to have a taste similar to a combination of raisin, clove, cinnamon and sugar."
http://examine.com/supplements/Hovenia+dulcis/

Here is a link that might be useful: Hovenia dulcis

If you want trees with a relatively narrow profile and a dense canopy, check out columnar European hornbeam, Carpinus betulus 'Frans Fontaine'. These make excellent screening trees, are relatively fast growing, adaptable to a range of growing conditions and are pretty much problem-free trees.

Where are you generally? What you can grow in LA is really different from what you can grow in south FL which is really different from Detroit or Boston.

If you want the callery pear trees they go ahead and plant the cleveland variety. It is supposed to less prone to damage. And is a fast grower.
Get what YOU like and not what other people like or dont like.

Sorry, should have detailed my region for you, I am in Pennsylvania.

And needinfo001, thank you for your response. I will ultimately choose whatever appeals to me best but I also wanted to get some other suggestions to look into. I really couldn't find many choices except for the pear trees when I searched online. Just wanted some other educated opinions before deciding.

Good Sunday morning to you. Maybe something like Nishiki Willow? I've seen one in my neighborhood in NY zone 6, tree form and it puts on a lovely, very dense show. I think it only grows 15' or so and needs lots of water. Plus I'm not sure when they leaf out or lose their leaves or what kind of debris they may drop in your pool though. If you like the look of Nikishi, maybe someone more knowledgeable could recommend something similar yet more appropriate.

A smallish fast growing tree would be crape myrtle and it would be blooming about the time you'd be using the pool so that would be a plus. Fall color can be really nice and the bark in the winter is very attractive.

I planted bigleaf deciduous magnolias next to our pool. They give it a tropical look. And the leaves are so big that they are easy to pick out of the pool when they fall in.

'Kwanzan' Cherry makes a colorful display in early May. It will not create a weed problem for your neighbors. Don't make the rookie mistake that this homeowner made and plant too close together.
{{gwi:358169}}

Serviceberry, Fringetree, dogwood, yellowood, black locust (all of these provide white flowers and are native)

Thanks everyone for the advice, I really appreciate it. I haven't decided yet but these are great choices for me to think over. Some like the Oriental Raisin and the European Hornbeam seem a little tough to find for sell online, but I will keep researching. Thanks again.