if you don;t like the blue, then put the blueberries on top after the oatmeal is cooked. I think it would taste better anyway. When i make blueberry pancakes i make sugar syrup, shut the gas and then add the blueberries and stir. I use it as syrup on the pancakes. You could do something similar, using only as much sugar as you like on your oatmeal, and lots of blueberries. you put them in frozen to the hot syrup wiothout further cooking and they defrost like that. Then the blue will be on top, and if you like, just marble it into the oatmeal, not mixing it, and it will be oatmeal with blue stripes, not blue-grey oatmeal which is not appetizing.