I live in south and want to plant shrubs underneath a large maple- this area faces west so afternoon and evening sun any ideas? Gardenias hydrangeas work?

Also could you verify the image for me? It's a perennial and I've been told it's a kind of phlox

ID - Phlox divaricata? Woodland phlox.
Maples have shallow roots which compete fiercely for water and nutrients. Hydrangeas are going to need ample moisture and perhaps shade in the south. Have you considered large pots set on top of the ground under the maple?

I'd go with Cindy's identification.
From the Phlox divaricata subspecies without petals notched at the tip.

Does look a bit like Phlox pulchra; just got some potted Phlox pulchra in flower and was reading about confusions between that and Phlox ovata. Quite confusing! I needed to stick with Phlox paniculata (garden phlox) which, given good growing conditions, looks so spectacular growing in summer, here up North.

Flower beds under maples; only have experience with a flower bed under/adjacent to a couple of silver maples and does my experience fit with Cindy's description! I need to dig out a foot (depth) of rootlets in the bed (with adding compost and replanting) to keep the variety of perennials in the bed going (do some part of the bed every year).

Perhaps shrubs could hold their own against maple trees, better than herbaceous perennials; but I guess it's the maple that's got the start.