Your plant appears to be a periwinkle (Catharanthus roseus). It looks old and as though it has been grown in its current soil for a long time. The soil looks compacted and wet. Are you feeding ...

the Madagascar periwinkle (Catharanthus roseus). Madagascar periwinkle, also known as "annual vinca," is a fast-spreading ground cover with lovely dark green leaves and dainty pink flowers all ...