I discovered  this by accident years ago, and it works nicely, so I thought to pass it along. It has to do with compounds in willow branches that encouage rooting in stem cuttings.

First you need a willow tree. Then what you do is this:

1. Gather a handful of fresh shoots maybe a foot long, strip all the leaves off and take the stems home. Cut them into pieces a few inches long, maybe 3-6”. Some say to boil water, remove from the stove, and cover the willow cuttings with it, and that may be fine, but I just soak them overnight in a jar with just enough water to cover the cuttings. We’re not talking brain surgery here. The soaking releases auxin (the hormone that encourages root growth). It also has to do with salsylic acid, the naturally-occurring analgesic in willow shoots. Aspirin, basically.
2. Dip the cuttings’ stem bottoms into the willow water for a few hours (into sand, or some other method. Think here people.)  Then just take them out and stick them into potting soil. They should begin to root within a few days.
3. This is fun. Give the results to your friends for holidays.