I built them from the workbench, and they haven't popped up. I keep trying, but it just says Large Planter added and nothing ever comes up

Has everything else turned up? It can sometimes take a while if you build everything really fast for all of it to turn up. Also if you left partway through furnishing, occasionally you might lose something, even though you build it and it takes the materials, it will never turn up. Did you try reloading the area to see if it is just a delay?

Are you sure you are actually building them, you had all the materials it required?

And an even weirder one.
You do have space for these large planters? You are not building something you have already built?


If you are missing the planters, and you and cannot build them, you should go back to a previous save game before you furnished the room, make sure you have everything you need before you start, and try again. Furnish the room in one go without leaving the workbench.

Got them to load up, but now within a few seconds of entering the house it freezes

You are at Lakeview Manor I take it? Remove any internal workbenches you are not using, especially that greenhouse one.

Personally I would just rebuild the house again.