Q: What has ears but cannot hear?
A: A field of corn.
Q: Why is corn such a good listener?
A: Because it’s all ears!
Q: Why shouldn’t you tell secrets on a farm?
A: Because the potatoes have eyes, the corn has ears, and the beans stalk.
Are you groaning yet? We make (bad) jokes about ears of corn, but it appears that plants might really have ears.