I have to agree that this is a beautiful shot, but doesn't meet the challenge. Sure, you could say that every single blade of grass is crossed with another and therefore forms an "x", but I think that when something is the theme of a challenge, it has to be very prominent - usually the most prominent aspect of the photo. Not sure if I said that well, but you probably get my meaning.
I expected this to place a lot higher. I saw X's all over the place in this shot including the one you mention in your notes. I think you are next to me in the rankings for the same reason. Our X's were not prominent enough as the subject. I gave this a 7.