[SKSuser]

Crazy thought here, but it could be something new to think about.
Willow tea is sometimes used as a rooting hormone in organic greenhouses and stuff.

What if the willow is giving something to the water instead of taking something away?

I may try a little project with willow tea in the spring when my willows get new growth.
BTW, I have many black willow and am willing to share for the price of shipping. They won't start leafing out here in MO for a couple months though.

 

[SKSuser]

Iceterrain,
I believe that it would work better if you waited until the buds started to grow. Its worth a try, and please report back with your findings, but I think it'll work better if the branch isn't dormant. I think it works best with the new branches.