We had armour stones put in as retaining wall, accent pieces/sitting stones and the ground surrounding the pool deck area is covered with small river rock.

Existing plants are spruce, cedar, boxwood, katsura, tiger-eye sumac, and grasses. We have removed a linden and birch tree (both very messy).

Thinking of adding golden threadleaf cypress, japanese maple and red-leaved wegeila (sp?) for colour, and I'd love some ornamental conifers for visual/textural interest. Any other ideas would be greatly appreciated, or if you could direct me to another forum that might be helpful, thank you!

I would use some of the ornamental conifers like you have mentioned, and lots of bulbs. Not real sure what grows in your zone, but bulbs are easy, don't drop leaves, and can give you lots of color. The conifers could fill in, even though they shed some. The farther away from the pool they are the better.

And you may find some other perennials like salvias, butterfly bushes, etc. that can give you color without large leaves.

You can also add Croton plants. Crotons love lots of light and have colorful leaves making them excellent pool plants whether it is potted or not. Also I have searched from Google for some pool landscape design. I hope this helps you. Thanks.

I'm also in the same boat...I think poolscapes are so important and I need more color around the pool area minus the mess..

anything red incorporated would pop against the blue of the pool water..