I made a poundcake with blueberries in it. But the blueberries fell to the bottom. How do I get the blueberries to do what they are supposed to do?
Tossing ingredients with flour is one way to keep them from sinking in batter, but that works best with dry things, such as dried fruit or nuts.
For your blueberry poundcake, try frozen blueberries. Frozen berries are less likely to sink. Fold them into the batter very gently, or put the batter in the pan in layers, sprinkling in some blueberries before you add more batter.
Now, the next question will be: "Why did the blueberries leave greenish-blue streaks in my poundcake batter?"
That's a chemical reaction that can happen if there's baking soda in the batter. That may not be a problem if it's a more traditional poundcake, which is leavened by beating air into the eggs and butter.
Again, frozen blueberries have fewer problems with streaks than fresh ones.