Why doesn't mistletoe grow up dogwood trees?

The joke “Why doesn’t mistletoe grow up dogwood trees? It’s afraid of the bark” is a play on words combining botanical facts with a humorous anthropomorphism. Mistletoe is a plant known for growing as a parasitic or hemiparasitic organism on various trees. Dogwood is a type of tree that, like all trees, has bark. The pun in this joke arises from the double meaning of “bark.” In a literal sense, “bark” refers to the protective outer covering of a tree. However, “bark” is also the sound a dog makes. The humor comes from whimsically suggesting that the mistletoe is afraid of the “bark” of a “dogwood” tree, as if the tree could bark like a dog.