I read somewhere that Weeping Willow branches don't need rooting hormone. In fact, if you take a branch and boil it in some water, that will itself make rooting hormone for other plants to grow roots.
I don't plan on planting one in the yard but I think it is nifty that a branch from this tree will cause other plants to root out. I am taking a gardening course too. Of course not having that, I use honey as a rooting hormone when I need one.
This page contains the following solutions.
Making your own rooting hormone with willow water. Here's what you do: Get a handful of willow twigs (any Salix species will do).
Honey is a great natural alternative to chemical rooting based rooting hormones. This is a page about using honey to root cuttings.
