Posted: 08/07/2017 at 17:34
Aeoniums are easy to propagate - handy as they do tend to succomb to the UK winter if you leave them out all year - particularly if the Autumn/Winter has been wet.
From your pic, the main stem has obviously rotted. Before you ditch it tho dig it up just to make sure the whole thing has gone. If not, cut down to a clean bit and pot up - an initial watering and leave it and see.
If it has rotted completely, Pete is right - take cuttings - for such an exotic looking plant, they are surprisingly easy to root. Sharp gritty compost - enough water to damp the medium - warm spot and you should have your forest in no time at all.
Summer isn't their dormant stage - that's when they will shoot up and produce more rosettes and, if hot and sunny enough, may flower. They do not require much watering - perhaps you have been too kind with them?