What to use to keep my plant upright?

Find & clean up a limb, tall & simi straight, the natural look is great!

I would use a piece of 3/4" PVC pipe. They come in 10' lengths and are easily cut. You can even paint it.

Use a long piece of bamboo - much nicer than pvc pipe

hi , from Canada use a tree branch to make look like part 0f the rubber tree

The tree branch idea from Canada is used alot ... may need to anchor it to another structure (wall, other tree ...) with cord(s) to stabilize it ; instead of relying on the branch to be simply stuck in the dirt.

First of all how tall is your rubber plant? I think what I would use is the side rail of a metal bunk bed. Mine has 5 metal bars and is 5-6 ft tall maybe 6-10 inches wide. You would need to connect it to a tall metal bar down into the soil or something of that sort. Mine is white and looks rather like a trellis. You could decorate what is above the rubber tree or put some kind of hanging plant or vine above hanging down. Or find a pretty shepherds hook.

Thank you for your suggestion, my house plant is 4+" tall w/a single skinny tree. Dowels come in 3" length and that is what it has grown past. I like the shepherd hook idea. Thank you