I put rocks in my garden years ago and still finding them to this day after removing them
about 7 years ago. The previous owner of our vacation home put them down in the front garden area and we removed them as the sun bounced off them and heated up the living room. They keep coming to the surface when we think we got them all out. I wouldn't recommend rocks in a garden area to anyone. Put down mulch it's better for the plants and the environment.