Cut several 1-inch diameter willow tree branches from this year's growth with clean, sharp loppers.
Remove all of the foliage from the willow branches and cut them into 1-inch sections. You'll need about a big double handful of these sections to make your willow tea. Split the sections from top to bottom to expose as much of the inner tissue as possible. Toss all of the trimmings onto your compost heap.
Cover the willow pieces with about 1 inch of water in a heavy saucepan. Use rainwater if possible, but ordinary tap water works.
Bring the pan of water to a vigorous boil, then remove from the heat. Cover and allow to soak overnight.
Remove the willow sections from the liquid, which will look like weak tea.
Set the cut stem ends of your cuttings into the willow tea for a few hours before planting them. You can allow them to soak overnight, if you wish.
Use the willow tea in place of water for starting your cuttings.
Store excess willow tea in the refrigerator. Take it out and bring it to room temperature for watering your cuttings while they're rooting.