RE: Lawn Mulch That Won't Kill My Dog?
I don't think rocks will work that well because these are all basically flower gardens. My folks had rocks in their flower gardens growing up and it was always a total disaster to try to move them when my mom wanted to plant flowers every year. And you can probably guess who had the job of moving all the rocks when she wanted to do that.
Maybe I can get some wood that's pulp or shredded up so it doesn't have any of those fun sticks.