I would not plant anything in ground there. I can’t tell the dimensions of space height & length but I’d get a planter - long & deep & however wide you need & fill it with planting soil. Sunny afternoons - ok but where? Texas or PNW? All that rock around the area will make it hotter by reflecting the heat so there’s that to consider for heat tolerance. Succulents would likely work either place & there are so many to choose from. Many of them flower. Stonecrop Autumn Joy etc. Or, if you want low to ground, there are Hens & chicks. Endless options.

Please add some photos from farther back so we can get some context for this space.

Is this the front, back or side of your house?

What is your zone/location?

Are you trying to hide the wall?

Add some boulders on top of the gravel rock, then plant creeping Thyme or creeping Rosemary among them. Dig a small hole through the gravel rock for each plant.

No need to remove the gravel rock, the plants will appear to grow out of it like a rock garden.