Virtually all the vitamin C on the market is synthesized from sugar.
Natural extraction is too costly.
Anyway, rose hips are added to the vitamin C as a source of bioflavonoids which would occur in natural sources of vitamin C, and help the vitamin C to work better. There are many different bioflavonoids, each with their own effects. For instance rutin can help with vision, and quercetin is antihistamine. Bioflavonoids are also weakly estrogenic, antitumor, and help strengthen blood vessels, among their other effects. Rose hips come from rose bushes.