I just looked at the plugin again and I couldn't find anything that can make the pieces roll.
The pieces are supposed to fall and stick into the grass but I agree the smaller pieces should roll a bit. If you notice though the particles roll.
I updated the explosion a little, I made it in such a way that a little bit of the base still stays. I don't think it is worth uploading unless some one really wants to see it.
You should be getting un update soon.