10 years ago when Hazel was less trendy I would have been totally on board with naming a little Boy Hazel. Now I am not so sure. I think that a lot of nature names are gender neutral but there are a few that are pretty tied to either one gender of or the other, Hazel seems more in the Lily or Rose category than the Rowan or Linden category. But I do like the idea of Hazel on a boy.