Hi Woody,
This sounds like a great experimental
project!
I don't know what your climate is so I don't know how relevant my
answer will be. (hint: add your location/climate see:
https://permies.com/t/29890/tnk/edit-profile-show-location ).
We've done a similar experiment here in Ontario, Canada (garden zone 5). We plunked in some willow branches (?whips?) in the spring and just let them be. Well, we watered them fairly regularly with fishpond wash. Nothing seemed to happen for quite a while so one day in the summer, I gave a tug on one of the stems and it didn't pull out, but the second one did and it had tiny little rootlets on it. About a month later, leaves appeared bit by bit.
We did put mulch on when we knew were going to be away for a week during our vacation. About 2 - 3 inches. When we returned (only 6 days later) a whole bunch of leaves (relatively speaking) had appeared, even on the stems that had seemed dead! So, yeah, I would recommend mulching.
Let us know how your experiment goes.
Debbie