Hothouse was originally published in the Magazine of Fantasy and Science Fiction throughout 1961. It won a Hugo for Best Short Fiction in 1962 and was published in book form in Britain the same year. An abridged version entitled The Long Afternoon of Earth was released in the States, and it wasn’t until 1976 that the full version was made available there.
The story itself concerns an Earth that has stopped rotating on its own axis and about the Sun. One half is permanently in sunshine, the other in darkness. On the bright half, vegetation has grown out of control. A giant multi-levelled tree dominates everything. Among its branches live the remnants of humankind, short green people of limited intelligence. They and a few species of insects are all that is left of animal life. They are vastly outnumbered by a plethora of mobile vegetation.
The story is a quest which takes its main character Gren, and others to the dark side pressed on by a symbiotic fungus attached to Gren’s brain. The book is a tour de force, its main objective to present a provocative picture of a truly alien Earth in the distant future. When it was published, critics like James Blish slammed it for being woefully unscientific. But Aldiss wasn’t trying to be. In fact, he had thrown science out of the window totally in order to apply liberal dollops of artistic license. The Earth simply couldn’t stop spinning or orbiting the sun and if it did, there are all sorts of things that would happen to ensure that all life would cease to exist.
Essentially, while this novel is presented in a science fictional manner, it is really a fantasy. Labels aside, I’d advise throwing caution to the wind and enjoying the book as a bizarre and evocative picture of a seriously strange world that is populated by outlandish creatures described in loving detail.