[Cami]

First and foremost Boxers are not outside dogs.
That being said you have to train them not to do certain things, like staying out of your flower beds. You can't do that if they are outside and you are inside. Puppy's need constant supervision for not only training but to ensure they don't get injured. One bite of a simple plant can be deadly.
Please rethink your decision to house your Boxer outside. It is not a good decision on so many levels that I don't know where to start.