I'm not an expert, but I do have a huge old rubber tree, and have rooted a small branch that broke off. I made a clean cut and put a little cinnamon on it (heard it stops fungus...?) put it in some dirt/perlite mix on a heating pad under a light, and kept it fairly moist, and it took a while but it did eventually root and grow... hope that helps! good luck!

I only have experienced rooting these in mix but I root many other things in water.

Kindly give it more time, one week for water rooting is nothing; depends on the plants. Can take more time or less time, depending on the plant & the circumstances.

This plant will root fastest in a highly aerated medium (like perlite) that is kept barely moist. Even if you do get it to root in water, the roots that form are much different than the roots that form in soil. They are very brittle and will not transition well to soil because they will be extremely inefficient at water absorption.

Al

My rubber tree would take over the house if I didn't keep loping off the stems,lol. I just make a sharp, clean cut and plop them in a vase of water and forget about them for awhile. I discovered this by accident. I didn't expect it to root and wondered why it was still alive. Pulling it out, I was surprised to see it had rooted over several weeks of just sitting in a vase of water. I've been doing this ever since to keep my rubber plant compact and bushy. Keep no more than 2 or 3 leaves on the cut stem.

I then just carefully replant the rooted stem in the soil around the "mother" plant and make sure to keep it moist, since it has shallower roots than "mom".