since I now am trying to grow a grapevine I discovered one method you could try, hardish to describe tho

plant stakes either side of it firmly in the ground with wiring/string in between them horizontally taught, with it crossing the path of your tree,and then using another piece of string tie the plant to the wire, Ive no idea how well this would work for this so you'd need some pretty strong, long stakes that sit firmly in the ground surrounding the plant, and you can use several horizontal wires at different heights if you wanted to give it more support until its strong enough by itself.

Just a thought