What is mistletoe? Why do people hang it in doorways in December? And what’s with all that kissing? 

Let's start out with Mistletoe itself. It is not like a philodendron or a marigold. You have probably never seen mistletoe in the wild. That's because mistletoe is a very weird plant. Mistletoe is actually a parasite -- a plant that grows on another plant. Mistletoe can't survive on its own. In the southern United States, if you know what you are looking for, it is pretty easy to find Mistletoe. Wait for the leaves to fall and look high up in oak trees. You will find the mistletoe as green clumps of leaves and berries growing out of the oak branches. Mistletoe actually sinks its roots into the braches to get the nutrients it needs.

So where did the whole kissing thing come from? The truth is that no one knows for sure. But there are a couple of ancient traditions that involve mistletoe, and they probably have something to do with it.

The first comes from the Druids living in Britain around 100 A.D. These Druids thought that Mistletoe could perform miracles. They thought that Mistletoe could help cure diseases and protect people from witches. They even thought it could help people and animals have more babies. So the Druids had a special ceremony that would happen in late December or early January. Priests would cut mistletoe out of oak trees and then give the mistletoe to people to hang in their houses so that it would ward off evil spirits.

This probably explains why mistletoe became connected to Christmas -- the time of year is exactly the same. And it explains why people started bringing mistletoe into their houses. But what about kissing?

The whole kissing thing might come from a Viking legend. Around 800 A.D., the Vikings had a mistletoe story they liked to tell. Vikings had a lot of gods (like the Greeks did) and many of their stories involved these gods. One of their gods -- Balder -- was killed with a poison made from mistletoe. His mother -- Frigga -- was able to bring him back to life after three days by reversing the effects of the poison. Once she did that, she kissed everyone who walked under mistletoe because she was so happy to get her son back.

These days, you buy mistletoe in little plastic bags around Christmas time. You hang it in a doorway in your home. If you see someone standing under the mistletoe, you are supposed to kiss him or her. If you want to be proper, the man is supposed to pick one of the berries off the mistletoe after the kiss. It's a fun Christmas tradition!