“In een groen knollenland” is the opening line of a traditional Dutch children’s song titled “Al in een groen, groen knollenland” (translated as “All in a Green, Green Bulb Land”).
The song tells the story of two rabbits in a green land full of bulbs (knollen). One rabbit plays the flute while the other plays the drum. Suddenly, a hunter appears and shoots one of the rabbits, making the other rabbit very sad.