That's a good idea, those two plants will coexist very well! The phlox is so shallow rooted that it will not compete much with the lilies for soil nutrients.

Sounds like a great idea. I have a bed too,. that I wanted to plant roses in, but I think its too narrow. You give me a great idea. I love both phlox and lilies and think they would do great together. Good luck with yours. Now should we color-coordinate them????

Just a thought here. Voles like to harbor over winter in the thick shallow cover of the dense dormant phlox. This cover also retards ground freezing allowing them to dig easily and they can be devastating to a lily garden. The same affect as putting winter mulch cover on before the ground freezes. I suppose if one would cut the phlox back real short it would be OK; or if you can keep phlox in clumps here and there. But, I know from my own personel experience they love those phlox under the snow in winter. Just a thought.