Unfortunately I'm not really feeling this. The the plant monster is not particularly interesting in my opinion, and I feel the role of supernatural gardener has been done before, and is not particularly interesting here.
On top of that, the part that I felt served as the most promising source of horror (the monster turning people into fertilizer) was glanced over and thus the article just doesn't come across as that scary, or even that creepy for me as a reader.
There is certainly fertile ground (pun intended) for this to be turned into a proper horror article, but as is, this just falls flat.
-1.