Would it take 20 years to get a 3.5" trunk for JBP? I wish to put mine in the ground and then, fertilize super heavily.
Thanks
You know, it very well might.
I was just telling a friend that I think that the idea of growing large-size bonsai from seed in containers is something that takes an entire lifetime. The largest of my 2006 batch of seedlings has not much more than a 2" trunk. They've been container grown the entire time. If I had wanted a larger tree perhaps I should have ground grown some of them, or placed to colanders on the ground to allow the roots to escape.
There's this whole mythology around bark quality in container grown trees versus ground grown ones but it seems like getting the trunk to size in a reasonable amount of time trumps the bark quality concerns. I think you could have a 3.5" trunk it 10 years with 3-4 years initially in containers and then 6-7 years in the ground. The problem is that once in the ground you need to pay close attention to balance. BVF has some that are receiving the proper attention but even really good growers can have the trees get away from them.
Check out this field of JBP and Cedar at Jim Gremel's place (That's Jonas contemplating the work needed):
These trees are less than 10 years old and they have 3" or 4" trunks in many cases. The branching has been left a bit too unmanaged though so he's got a long road ahead of him to make good pine bonsai.