I concur - male nature names aren't popular the way female nature names are, but they're not unknown - Rowan, River, Stone, Oakley (ok, I'm stretching lol), etc. I can see Hazel as a slightly odd but legit Victorian male name.
♦ Chrisell ♦
All we have to decide is what to do with the time that is given us. - J.R.R. Tolkien.