The colour ‘green’ is associated with hope. Or with poison. This is because of the green paint, which was quite poisonous at 19th century. The favorite colour of Napoleon was green, so in his exile walls and furniture were designed in green. As a result he died of a slow arsenic poisoning. So the german language kept this unwholesome history by the expression poisonous green despite of the greens main appearance being associated with freshness and health.