I have some underground PVC irrigation tubes that people keep breaking open when they dig a hole for plants. I want to document where these things are running throughout the landscape so that I can minimize the chance of this happening again. Ideally, I would like the marker to have some documentation on it, so I can show which zone is being fed by that underground pipe and what is the direction of water flow. Can someone recommend a decent cheap landscape sign/marker that I can buy for this purpose?

On Amazon, I found the usual landscape "flags" that are used as a temporary marker during excavation and construction. Those are not suitable aesthetically for a permanent installation. I also found landscape markers used for marking either side of a driveway that is under snow. That's too large for my application. I need something that would come up maybe six inches from the ground level, and would have a small flat area where I could add in a few words to document what is below the sign. I suppose I could also use the same signs to provide names for in-ground plants.