The day of the triffids - John Wyndham

The risks of genetic engineering become horrifyingly real in this post-apocalyptic tale of the collapse of human society, and nature's revenge.
When Bill Mason wakes up in hospital after recovering from eye injuries, he peels the bandages from his eyes to discover that the rest of the world has gone blind and a deathly silence hangs over everything ... A future of chaos and violence awaits him, but the greatest threat to civilisation is yet to come: the Triffids, genetically-engineered plants who feed on human flesh. Sensing their newfound ecological advantage, they quietly escape from their confines and seize their day ...