In the hg/ss johto safari zone wetland I've placed 21 peak objects and waited seventy days. I've been walking around a long time and I am yet to see a shelgon. What's the deal?
It's just a matter of time and repetition my friend.
My god I remember walking for three days before I found the right Pokemon. So patience, and time.
YOu have all the right ingredients so now you just have to keep at it.