Question: I accidentally knocked a leaf off my rubber plant and have placed it in a glass of water. Will it root and produce a new rubber plant or am I simply wasting my time?
Réponse: Your rubber plant (Ficus elastica) leaf may well root, but it will never produce a new plant.
Ficus leaves, especially those of large-leaved species—the fiddle-leaf fig, F. lyrata, for example—do have the capacity to produce roots from a leaf petiole if conditions are good. However, what they don’t have is the capacity to produce a new plant from a single leaf. There is no dormant bud on a ficus leaf that can eventually grow into a plant. You’ll get plenty of roots and the leaf may live on for months, even a few years (you’d have to pot it up into soil for that), but it will forever remain a single, lonely leaf.
Rooted leaves that never produce shoots are said to be “blind cuttings”.
On the Internet, I often see thrilled indoor gardeners marveling over the leaf cuttings they took of a rubber plant: “Look,” they crow, “my leaf has roots!” They all look forward to the huge and beautiful rubber plant it will one day become, but they are going to be bitterly disappointed.
Now, if a piece of stem were included as part of the cutting, that would change everything. A stem cutting of such ficus plants, even only one with a single leaf, does have a dormant bud, found at the leaf base. So, if the stem roots, the bud will begin to grow and will soon produce a new plant.
But a leaf alone will be forever blind.
There aren’t many plants that are capable of producing an entire new plant from a leaf cutting. African violets, streptocarpus, sansesverias, sedums, echeverias and (some) begonias are exceptions and will readily produce new plants from a healthy leaf. But none of ficus varieties will.
Sorry to disappoint you!