Yeah a Ginseng Ficus is a cultivar of a Ficus Retusa or Ficus Microcarpa, or the also called Tigerbark Ficus. They are not really grafted, the tuber roots usually grow underground and then are exposed and planted up and then chopped off just above the thick roots, and as Ficus do, fine new growth sprouts form the top. The exposed roots look like ginseng and thats where the name comes from, I have seen them called pot bellied ficus too. You cant kill them with a blowtorch, they can be chopped, air or ground layered and will grow from branch cuttings of almost any size and without using rooting hormone, just stick em in wet sand, spaghnum moss or plain potting soil and in less than two weeks they are growing great roots.
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