The great bloke did just that for me and when I got home and unpacked from the day, I cleaned it up and potted up into a poly box to recover for a year or so.
I love Hibiscus and hopefully I can do it justice as I do not think they are done anywhere near enough in Aus, time will tell.

The initial shots of it are below and I hope it will make a real nice progression thread in time.
I cut off the bottom of the root mass and stump then soaked in Seasol.
For the interested, I have got some Pumice to add into my Mix so will see how that goes now

Ken