The July/August reader created one?
Crack it open and turn to page 22. There we are, on the Plant Tags story! (In the middle, the stamped concrete marker stones).
Funny thing is, this is probably the ONE thing we've done at the house that has been a kit, not an insane custom, handbuilt thing. Ha!
There are other cool plant tag ideas on the 'bonus' page online - I LOVE the license plate one.