Rose a mix of red and white?
I think not. The grapes are "red" skinned but "white" inside. You can make a white wine from them (chuck the "red" skins away straight after pressing), or red (skins stay throughout fermentation) or rose (macerate until it's as red as you want).
It's a bit like saying that if you mix stout and lager you get bitter. Speaking of which, mine's a Pedigree.