Wow, this must have took ages to render
I really like the mood in this image, achieved by the lighting.
Don't know what you did with the grass lumbs, seems like they have small spotlights inside? (especially grass at the far left)
A nice effect, but maybe a little bit overdone.
The agaves look very nice, so does the lighting on the flowers (don't know which model that is).
Maybe you could add a little more variation in the groundcover. More bumpy mixed fractals and some small fake stones.
The texturing on the fake stones look good, nice bumps and fractal variation. Don't want/like to 'promote' my post about cracked stones, but you might consider to read it, since it can give realistic results.
http://forums.planetside.co.uk/index.php?topic=1939.msg19180#msg19180You also might consider to work a little on the thick low clouds by lowering the glow amount and to add more softness and contrast.
The POV is very well chosen, I'd keep it that way for sure.
So in conclusion a very nice image with great potention and which can use some touch-ups, but I think they aren't impossible at all or extremely much work.
I'd certainly like to help you.
Martin