This looks more like something small made very large. The challenge was to show a miniature version of something making it clear that it was a miniature version of something. This doesn't even appear to be a case of mistaking the challenge for a forced perspective challenge since this looks like it actually is a large sculpture, not a small toy shot from an angle to make it appear looming and large.
"Compose and photograph something "miniature" in such a way that it conveys to the viewer that the subject of your photo is a tinier version of something that is normally larger."
The challgne was to take a minature of a larger object, this seems to be the opposite of what the challenge requested. Nor are plants a good use of minature since they come in all shapes and sizes.
That aside I like the leading lines and the DOF in general. Also got a nice blue sky, but even if it met the challenge I suspect this picture would be mid 5's,