Foliage Being Lit Through Landscape

Hi all,

I have a world with a day-night cycle using a rotating directional light (and the Geographically Accurate Sun Position Actor). My landscape has loads of small rocks (foliage) and when it becomes night, and the sun is underneath the landscape, my rocks appear to glow at the bottom. I realised this is because the underside of the rock is being lit through the underside of the landscape. Is there any way to stop this? (I tried making the landscape material two sided and that didn’t help)

Here is a picture of my rock at night, but it’s quite hard to see so hopefully my description is detailed enough.

On a larger scale, you can see why my problem is really obvious:

Thanks!