There's a good introduction in this edition that discusses, among other things, how this work compares with John Wyndham's Day of the Triffids and William Golding's Lord of the Flies. In that analysis Day off the Triffids comes of badly.
The reason for the comparison is obvious: both are apocalyptic SF novels where plants are at the root of the problem ( Ducks flying rotting vegetables in response to that pun. Oops, another one slipped out...
) set in Britain by British authors writing in the same period of the 20th Century. The introduction is very dismissive of Wyndham's effort, basically because the book is more optimistic than Christopher's, which is unremittingly grim, right up to the last sentence. However, my feeling is that there is not much difference in their view points about what would happen in the case of the total break down of society; in Wyndham's case there just happens to be a place where that hasn't happened. The conversations characters have about women, work, education and marriage reherse exactly the same arguments and attitudes, but Wyndham's heroine has the most progressive attitude of any of the people in either book. She was a gal ahead of her time.
Where Christopher is more successful than Wyndham is in his basic scenario, plot construction and braver characterisation. The idea that a virus could wipe out all species of grass is a lot more plausible than that of herds of sentient, mobile plants on the loose...the journey to re-unite family and find a safe refuge in the face of national or world disaster is now the stock of an entire sub-genre of Holywood films...but neither Wyndham, nor Holywood (most of the time, anyway), takes as protagonist a man who is willing to consider any action in order to save his family, or what real psychological pressures of that kind might do to him when he adopts a leadership role. This latter is what really makes The Death of Grass stand out - and what calls to mind Lord of the Flies. The difference there is that Lord of the Flies examines the process of establishing leadership by contrasting two characters; one the most likely to get everyone through their ordeal safely, the other, the naturally charismatic leader with a will to power. Christopher instead shows an evolution of character in his main protagonist from Piggy to Lead Choirboy (whose name I can't recall).(This analogy works in approximate terms, only.)
The book is well thought out, well constructed, well written, has a good ending and takes an interesting, not oft examined approach to moral questions that puts me
in mind of Roger Zelazny's more extreme character arcs in Jack of Shadows and Changeling and...J.G. Ballard. It is perhaps this latter that makes me give The Death of Grass only three stars instead of four: I recently read Rushing to Paradise, which also examines the breakdown of society but is, somehow, a much more thrilling, frightening and gripping read.