The inspiration for the story came from several stories, not least of all eco-disaster TV dramas from the 70s and 80s - namely the BBC's adaptation of The Day of the Triffids and the classic Doctor Who adventure The Seeds of Doom.
I recently discovered that the writer of The Seeds of Doom, Robert Banks Stewart, as well as being inspired in part by John Wyndham's tale of vegetable vengeance, lived with his family close to Kew Gardens which directly inspired billionaire Harrison Chase's estate. Banks Stewart is even supposed to be descended from Joseph Banks, the botanist who took part in Captain Cook's first great voyage and was almost single-handedly responsible for stocking Kew Gardens in the first place.
I think, subconsciously at least, another of the inspirations for my story Fruiting Bodies was this illustration by Martin McKenna of a plant golem, that appears in the Fighting Fantasy gamebook Legend of Zagor.
As any fan of the Fourth Doctor's adventures will be able to tell you, McKenna himself was inspired by the humanoid form of the Krynoid, the alien intra-galactic weed that threatens Earth in - you guessed it - The Seeds of Doom.