learning responsibility does matter. So I'd focus on that. Set up daily responsibilities that you want her to work on over summer and work on her completing these responsibilities on her own without prompting (which will likely not be perfect at first of course!). Some of these goals could be family chore related, but have some academic goals, maybe for a certain amount of time on Khan Academy, reading certain books (maybe you set a goal with her of a certain amount of reading, or reading books of a certain caliber), scripture study, etc.

BTW, this was my son's problem too and this is what we'll be doing this summer. He did fine on his tests, but failed to turn in any homework. I'm not sweating it, but we are going to spend this summer working on daily responsibility.