One method to propagate new plants is from root cuttings. This is a thick piece of root that I cut off during the potting  process. I selected a root that showed some nice movment and planted the lower end into bonsai soil. I watered as needed and in 6 month’s time the end of the root sprouted new leaves and stems.

Not all Ficus will grow from root cuttings but one fig that does particularly well is Ficus tremula.