If that's a possibility, I think I'll decline to plant a seed. The risk seems too big. Horror is one thing; a planet of horror is another.
But would the horror be planet-wide? Of course. In sci-fi planets are always ONE THING. Wikipedia:
The inhabitants of a planet called Iszm, a species known as the Iszic, have evolved the native giant trees into living homes, with all needs and various luxuries supplied by the trees' own natural growth.
One guy tries to steal the seeds, and since the idea is rather thin to begin with, it only takes 30,000 words to tell the story.