I don't have experience with anything but corkscrew willow, but I can tell you without a doubt, the larger the branch, the better success I had. The pencil thin ones were hit and miss, whereas the ones that were cigar size or bigger rooted readily and vigorously. As long as they are kept inside out of the cold, and you use a fine watery peat mix to root them in, look out - they will explode in roots.