I once made a bonsai tree using MTree, which no longer works. It was OK, nothing special, but I had been mucking about with the materials and it was a good test bed for that. I tried to recreate it using the sapling tree generator. This is what I came up with and it is similar. The tree itself has three different materials which are the same apart from levels of bump and displacement with more for the base of the trunk, less for the main branches and even less for the twigs.
Unfortunately you can’t easily separate the leaves from the tree and if you apply a subsurf modifier to the tree you also apply it to the leaves, which I didn’t want. In this version I duplicated the tree without the leaves and applied the modifier to that and then hid the original tree without subsurf but not the leaves.
I have since worked out you can duplicate the tree without the leave and apply subsurf to that and then duplicate the leaves without the tree and put it and the duplicate of the tree in a new collection and you can at least control the tree and the leaves at the same time by controlling the contents of the collection.
As with most things Blender, this isn’t me complaining - the add on is free and packaged with Blender so I very happy about that - this is me explaining my way round what appeared to be a bit of a problem in the hope that if anyone else is getting stuck with this I can help them.