How to decorate and put color into a a phoenix backyard?

Cactus in Very Colourful Large Container's Other plants too in Containers. Sculptures - Statues and coloured glass chippings - Coloured stones etc.......

Sometimes simple is more elegant. That being said, I would limit the colors of the lawn furniture and accessories and let the pool speak for itself. Google photos of hotel pools and use that as a guide.

try adding a picture of the space in question because that could provide the size and type of space provoke more ideas.

so I'm a fan of colorful bushes that dont shed leaves!

I've got a beautiful water fountain. Size and color would be determined by your space.