“I have a small planting area with perennials that is currently mulched with ½” gravel. I would like to add regular insulating mulch under the stones. Should I remove the stones first? Or can I layer mulch and new stones on top of the old ones?” – Mrs. T
Generally speaking, most people use just one kind of mulch, so if they are using stones they wouldn’t add any other kind. The exception to this would be if you are in a very cold climate and need the insulating protection of organic mulch, or if you want the nutrients and other benefits of organic mulch but like the visual appeal of the stones.
In looking ahead, I think if you layer organic mulch, and more stone, on top of existing stone, you’ll eventually wish you hadn’t. That mulch is going to break down over time and mix with the buried stones, leaving you with a rocky, earthy mix that will frustrate you and your shovel next year when you decide to plant something new.
By keeping the stones only on top, you can rake them out of the way, plant a new perennial, and rake them neatly back into place.
For more information, see our article on Using Mulch in Your Garden.