Plants/Flowers that flower every year

I have a stone wall outside my house that divides my house from my neighbours and there is a hollow in the wall so I would like to fill it with some topsoil and set some flowers/plants. Could you advise what flowers/plants that I can set that would flower every year i.e. and also that would be low maintentance, so that I wouldn’t have to be replanting again next year and also what could I plant there that would grow all year. I would be planning in planting in the next few weeks.