I have rhubarb that has grown from seed and appears to have done well. I've resisted the temptation to harvest it as it was its first year. The leaves have now died and are wilting yellow on the ground. I think I need to cut them all off but some of the advice mentions not to disturb the new crown emerging. I can't see anything but it could be buried a bit as it is fairly well mulched. Do I cut them back to the base? Do I need to do anything else apart from maybe mark out the spot so I don't dig or weed in that area? Thanks.