Hi, welcome to GoY, when you say ''Rehum'' do you mean Rheum x hybridum, the edible rhubarb, or 1 of the other 49 species, which are grown for their large basal leaves and tall flower spikes, but whichever you have, without a photograph of the plant, it would be impossible to tell if it's rotted beyond return or not, the only thing is to wait until growth starts in spring,{or not}, if there is no growth by about mid april, I would say it is dead, Derek.