Jennifer Forman Orth reports from the front lines of the battle against the Japanese knotweed that is choking off native plants in Franklin Park and elsewhere in eastern Massachusetts:

Turns out zookeepers harvest the stuff in the park and feed it to the giraffes, who respond to it like kids at a self-service softserve machine. In fact, zookeepers credit the knotweed with helping save the life of one giraffe who had come down with a wasting disease - it was the only thing he'd eat.