My cousin picked out a butter cream wedding cake with fondant grass shoots around the tiers. Some of the grass pieces extend above the top of the cakes. Do I need to just cut the fondant grass pieces and let them dry before adding them to the sides of the cakes or do I need to add something to strengthen the fondant? Would the remove the grass before serving? I wouldn't want everyone to have to eat hard crunchy pieces of fondant.

Make them out of gumpaste, it's not a big deal to remove those and they'll stand up better.