Answer: I'm sorry about your plants! There are several possibilites; woodchucks and deer both damage plants like that. Deer in particular will bite off a big section and then drop it if it isn't to their liking and other preferred foods are easily available. Any time there is physical damage like that I suspect human intervention -- small children investigating or causing mischief, me with the hose or absent mindedly stepping on it, accidental weed whacker attack, the basketball hit it, that type of thing. It may take a little detective work to figure it out.
In the long run, it probably will not hurt your plants to have been "pruned" that way, in fact, they will probably grow back thicker and bushier and better as a result. In the meantime, good luck with your detective work!
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