Would it have been rude to refuse to accept free garbage? She was essentially offering you her yard trash.
Rosemary is yard trash?
It can be. Anything can be trash if its not wanted.
A friend of mine was lamenting all the weeds in her yard. I walked around a bit and pointed out all her "weeds" were mint, dill, chives and basil. She doesn't cook but wanted a nice lawn, to her they were weeds. Rosemary can grow pretty big and there's only so much you can do with it, so at a certain point, it becomes yard trash.