There is no shar'i problem with a man growing his hair, as long as it is socially accepted within the 'urf of the Islamic community that he lives in and as long as he does not bring criticism to himself from other Muslims.
As for something like braiding or plaiting his hair, I'm sure you would agree that these are things women usually do. A mu'min must observe the highest level of good character in not only his moral conduct, but also his appearance. He must ask himself "do I look like a mu'min".
I believe if we were to take this approach, we would be able to quickly discern what we as mu'mineen should be doing and what we should stay away from.
And Allah knows best.