Step 3: Dress it up
Here's the treasure I found, as I was digging the hole I found these rocks buried there by a prior owner and used them to border the pool. My wife, the landscape designer said Oh, that's, umm, nice ;-).
If you absolutely must add plants, go ahead but locate the pool in a spot where it gets 6+ hours of sun a day or the plants won't do well. Eventually ground covers will be planted around the pool.