Do you propagate a lot of plants from cuttings? If you do then chances are you are a user of rooting compound. I know not everyone swears by it but there are certain advantages, especially if you are dealing with very delicate soft celled material.
Rooting compound acts both as an inhibitor to fungus, bacteria and viral disease but also stops the cut you have made with a knife or secateurs from healing up - very much like the way in which Aspirin (derived from Willow ~ Salix) acts as an anticoagulant for stroke or heart sufferers who need to avoid blood clots or the bloody thickening).
Plants produce a chemical called Absicsic acid which assists the plant in healing any wound by restricting the flow of liquid to the damaged area. Salicylic acid from the Willow blocks this process of inhibition thus allowing growth.
All Willow trees contain a naturally occurring chemical called indolebutyric acid or IBA. By collecting and boiling fresh twigs from the willow it is possible to extract this chemical and use it as a rooting compound.
How to extract hormone from Willow Bark
Cut some stems from a young branch and chop them into lengths of 75-100mm (3-4 inches). A bunch of stems held in your hand allowing you to connect your fingers and thumbs around the outside will make about 4.5 litres (1 gallon).
Boil a kettle and prepare a plastic container that has ideally been sterilised - boiling hot water or microwaved. Put in your willow and pour over the (4.5 litres) boiling water. You now need to cover the plastic container. I use cling film but a cloth is ok.
Leave the solution to stand overnight. The indolebutyric acid will be released into the water.
Now, seal up the container and make sure you label it. Pop it into the fridge to keep fresh until it is needed.
Using your solution
When you have prepared your cuttings it is best to stand the tips that will be inserted into the compost in the solution overnight. Doing this will cause an infusion into the bark and stem, inhibiting infection and encouraging growth.
It is best to pour out what you need when you need it so as not to contaminate your supply. This will ensure your batch will remain viable for 2-3 months. However, it is so easy and cost free to make to make that you can knock up a fresh batch every week if required.