I have a few small evergrren shrubs around my pool. I plant taller growing annuals in a 3ft bed surroundind the pool to help disguise it, but they are not cottage garden flowers. I have different varieties of daturas, gladioli, and dahlias. It looks tropical and hides the ugly white metal pool sides quite well.

the main thing to avoid is plants that will shed leaves, seeds, spent blossoms, etsc. into your pool and plants that will attract bees and wasps to its area.

I have read that Firmiana simplex- Chinese Parasol Tree will give a pool area a tropical look. If a tropical look is desired I would plant a half dozen Magnolia macrophylla-Bigleaf Magnolia. The leaves are almost 3' long and 1' across. Also has large, fragrant,white flowers in time. Lends a large banana plantation look to an area. Cover the pool when abscission occurs.