I have been using aspen for the garter since it's what I use for the BPs as well. When I would feed the garter, she'd drag the pinkie parts over the aspen, collecting unwanted pieces of aspen on the food. I became worried that she'd ingest some, so I decided to clean out the tank and put some reptile carpeting (what I use for the leopard gecko,) down. I haven't seen this used for any else's garters and was wondering if it's just not recommended for them. She's able to go under it and "play" around there, then comes out to bask and climb all over the branches and vines. At the same time, she doesn't seem to appreciate not being able to make tunnels like she did in the aspen.