I had three this year. The first was on Aldersgate and then two from Green Arrow. Aldersgate was the first thing to bloom so the prolif is older than the other two by nearly a month. I left it on the scape until the top of the scape had died completely down to the prolif, but I got worried I'd forget it was there. I didn't really want water roots, but I wanted to see what was going on with it, so I fixed up a plastic water bottle and filled it with dirty creek sand and left enough of the lower scape to stabilize it in the sand at the right level and then filled it water. Seems to have worked. The Green Arrow scapes made pods, so the prolifs there had a lot longer time on the scape and got bigger and showed more incipient air roots. I can see Roots through the sides of the plastic and growing in the bottom on all of them. A photo of the three in dirty sand. They've been in a south window inside since I removed them from the scape. The smallest is Aldersgate in front:
Here's the Aldersgate prolif after being dumped out ready for planting in a pot, it didn't have even much sign of air roots when it got put in the sand:
Here it is in a 6-7" standard clay pot. This wasn't what I'd originally planned for it, but it may be how it lives through the winter:
The two Green Arrow prolifs have to wait for another day. They are larger and the roots showed up faster than on the Aldersgate prolif, but they haven't been in the sand nearly as long. Back in the window for them!