When I realized Garen wasn't that OP. I know I shouldn't experiment in ranked, but it worked. I rushed 
and 
against Garen, he still melted my health as I melted his while we were trading, but his ult did absolutely nothing... then I killed him.
It used to be somewhat common to build hex drinker against Garen if you didn't need extra defense against him and his jungler is AP, but that was quite some time ago and the champs who did best with that sort of thing fell off. The shield from it will completely absorb his rank 1 ult.
Right now, with his nerfed low level damage, it's usually better to rush damage against him. It forces him to decide between continuing his usual build and playing safe, or staying aggressive and building tank first. Push him out of lane, take his tower, and end the lane phase before he starts to rev up in the mid game.
The boots are definitely good if your champ is weak to silence, but Spirit Visage is a bit much. If you really want to go the tanky MR route in lane get the cowl and stop there (unless his jungler is magic damage heavy and likes top lane).
It all depends on your play style of course, so in the end you're the best judge of how you want to handle the matchup. All I can say is as a Garen main since season 1 an early Spirit Visage wouldn't have stopped me very much. Especially early on if you can get a kill without ulting it's often best to do so.
