These substances work through different pathways in the body and do not interfere with how each other is absorbed, broken down, or used by the body. Rosehip is a natural source of vitamin C, so taking it with a vitamin C supplement simply increases your total intake of that vitamin.
This is a companion discussion topic for the original article at https://de.patient.info/medication-interactions/devil-s-claw-and-rosehip-with-vit-c-interaction