Hello all
I have just be given a 1 year old graft of Acer Palmatum 'Shindishojo'. The root stock is about the diameter of a pencil but the rest of the tree seems to have grown very very thin. It is about 20/25 inches tall and the gaps between the leaves range between 3 and 4 inches

There a couple of side branches that are no thicker than the trunk (about 1/8" if that) and growing straight up along side the main trunk. Its that frail that it wont support its own weight (I have it staked ATM) It is only in a small 3 inche square pot ATM and come spring I was going to put it into a much bigger pot (8/10 inche?) From what I have read on this forum that should help increase its trunk but I get the feeling that this little grafting is going to require more than that! Any advice or recomendations would be most appreciated. Please bear in mind I am a Bonsai Noob and by the way I cant plant it in the ground either.
Cheers
Adrian