Native Americans were possibly the first ones to discover they could make willow water to stimulate roots to grow in different plant cuttings. Nowadays, you can buy root stimulators that have a synthetic form of indolebutyric acid (IBA), the same substance present in willow branches that induces root development. But if you have access to twigs from any willow species, you can easily make your own root tonic at home.
Making Willow Water
Collect about 2 cups of willow twigs. If they have leaves attached to them, trim and discard those before you begin to prepare your willow water. Then, cut the twigs in 3-inch segments or smaller.
Either put your willow sticks in a metal bucket or a large glass jar. You'll need a container big enough to hold your 2 cups of twigs and 1/2 gallon of water. Boil the water, pour it over the willow pieces and steep them as if you were making tea. Let them soak overnight or for eight to 10 hours. Do not cook the sticks with the water when you're boiling it.
If you're involving children in this gardening activity, use lukewarm water instead to prevent any accidental serious burns. In this case, you'll need to soak the twigs for up to two days. The longer you steep them, the more indolebutyric acid your root stimulator will have.
Using Willow Water
There are two ways you can use your willow water. One is to plant the cuttings that need roots in the ground. Then, water them with your homemade root tonic. Two applications are usually enough, but it's hard to know for certain how long it will take for the roots to actually begin to grow. One telltale sign is the appearance of leaves. You can also test by giving the cutting a gentle pull. If you feel resistance, roots are developing under ground.
Another method is to put the cuttings directly in the willow water, but do not reuse your root stimulator once one batch of cuttings has developed roots in it. Make a fresh tonic for the next batch. With this method, you can easily see when the roots appear.
If you end up with any unused willow water, store it in a jar with a tight-fitting lid and refrigerate it for up to two months.