I love dianthus, & in my experience, they bloom on & off until frost.

My personal favorite is Barberry Pygmy. They do however have thorns...We only prune them 1 time a year in the early spring...we had them as a border plant with the west sun on them...did not seem to bother them...min water still...lots of luck...

If your sun is morning sun, Dianthus should work there. They do slow down in mid-summer, start blooming again in the fall and pretty much bloom all winter unless we have a freeze. Mine came through the freeze and are blooming again now. Some of them will die out if they get too hot.

Verbena would work well there too and can take more sun. They are annuals and will need to be replaced each year.

My verbenas are not annuals. I have a couple I have had for several year and they are blooming right now. I bought a couple of hanging baskets at a discount last year, and ended up relocating the plants to inground. They had verbena in them and both came back strong even after the terrible winter we had. I love Homestead verbena, and it is a perennial.

There are some lantanas that are redish, bagonias also, salvia gregiis, salvia coccinias hybrids. Some stay smallish, "Lady in red".

Carrie - Thanks for the tip on verbena. Mine seem to die out over the winter, but it may be that I don't expect them to return and pull them too soon. I'll be more patient and see.