hi girlwithglasses - and welcome. The data don't match the ingredients. If you used 12 lbs of sugar dissolved in 5 gallons of water then that is about 2.4 lbs of sugar in every gallon and at about 40 points (1.040) of gravity for every lb your initial reading should have been closer to about 1.100 and not 1.200. A gravity of 1.200 is potentially off the charts as there is enough sugar to make a "wine" that has more than 25% alcohol by volume but no yeast can deal with that and most yeast would be damaged by "osmotic shock" - the concentration of sugar being so high that this would injure the cell walls as they tried to transport the sugar from the outside to their insides.
CJJ Berry - a classic British home wine maker from the 60's - has a recipe for rose-hip wine where he used about 1/2lb of dried hips for every gallon. I see that he allowed the rosehips to sit in the must for 10 days but he had minced the rose-hips and had poured boiling water over them with the juice of a lemon to make a kind of tea, pitching the yeast when the solution had cooled (see his 130 New Wine Making Recipes, 2011). Berry also suggests that you add yeast nutrient - the rose-hips being nutrient poor for the yeast. If you did not add nutrient then that might explain why it has taken a week for the gravity to drop about 10 points. You can buy commercially made nutrient from your LHBS or you can, at a pinch, make your own by simply taking some bread yeast (say 1 T) and boiling it in a little water (I would proof the yeast first but that does not seem to be something that others do) . Your wine yeast will happily cannibalize the dead yeast cells and take the nitrogen and other organic compounds they need to make the sterols and other chemicals the yeast need to thrive.