just a long shot here, but worth a try i suppose if you haven’t done so yet:
try removing one of the planters in question, reload the game, then place the planter again, rename it and once more reload the game and check whether it was saved.
versuch mal den pflanzer wegzunehmen, schließe und starte das spiel wieder, platzier den pflanzer und benenne ihn um, dann starte das spiel nochmal und schau obs gespeichert is.
ps: did you use any umlaute or was the name very long? just for testing try using a short word without any special characters.
haben die namen umlaute enthalten oder waren es lange wörter? falls ja, versuch mal nen kurzes wort ohne sonderzeichen.
I have the same problem, but with stoves. I tried renaming the standard stove and when reload it’s back to its default name. I had the same problem with my large camp fire. After two or three tries, the name finally stayed on the camp fire. I still can’t name standard and upgraded stove. Names just won’t save.
Well, like i said, it was a long shot. I hope a solution to your problem will be found soon. =]
oh, another long shot idea: maybe test if you have the same issue when playing online on an official server, and/or back up your save file, make a new single player game and try if it still is bugged, if you haven’t tried all that already.
that way you could determin whether it is something specific to your current save file or to your game version