Willow has a natural tendency to root fairly easily in just a bucket of water, but if you look at the picture you’ll see a major difference. The willow with the green leaves and the roots on the right are ones which had their tops trimmed.
The cuttings on their left did not have their tops trimmed and thus for some reason did not leaf out or root? I wonder why this is?
I also discovered that you need to change the water at least once a week, or it goes bad and smells.