Trees flickering like mad in VR

Hello,

Sorry if i ask silly question, im fairly new to VR, so i made a nice scene sort of like a forest with a bunch of trees. When i play it in regular (non VR) is looks really nice, when i build it for VR it looks really bad, the trees flickering like crazy, especially the leaves when you look up at it with the sky behind it.

I have HTC VIVE.

Anyone know anything about this or how to solve it?

Thanks!