Gilraen Took

Well, I'll have a lot more after I plant everything(tank still isn't clear 150+ gallons of water changes later. I think I'm just gonna have to keep rinsing the filter floss a few times a day. . .) but there is one spot that I am curious about. I've got a rock with some java ferns glued to it(hey, figured it works for frags, so I tried it with a fern and it seemed to be okay since I was careful to not catch all of the roots) and it has a triangular area behind it that is probably. . . 4X4X6" on the sides and 5-7" high. I was kinda thinking of putting my big crypt(looks like a balanese?) behind it, or maybe some corkscrew vals when I can find some decent looking ones? What would you guys do? I don't like the way it looks so bare. . .