A leaf attached to some stalk has fallen off my rubber plant. Can I root it in water with some Stim-Root?
Rubber Plant, Ficus elastica, can be propagated by leaf bud cutting, tip cutting and air layering. The method most relevant to your question is leaf bud cutting. The cutting should contain the leaf blade (the leaf), the petiole (leaf stem) and a short piece of plant stem with an attached axillary bud (the bud arising from the join between the plants stem and the leaf petiole). If you place this in a growing medium and keep it slightly moist, in a warm, very light (but not direct sunlight) place, the new shoots should arise from the axillary bud in 8 -12 weeks. Soil temperature should be between 72-80 degrees F. For this propagation method, rooting hormone has not been seen to speed up this slow process.
There is a diagram on this website showing a leaf bud cutting. Unfortunately, planting just a petiole with its leaf attached won’t work with this type of plant. https://www.ces.ncsu.edu/hil/hil-8700.html