Black Wind/Cloud Waves in Kite Demo Grass?

Hello everyone,

So I’m trying to make a scene of a front yard and I’m struggling with getting the grass right.

The grass has these black waves that travel across the grass. I’m assuming it’s meant to look like cloud shadows?

Could someone please help me figure out how to get rid of them? Also, how can I reduce wind speed? The amount it waves doesn’t make sense for a front yard.

Thanks everyone for the help!