our sago palms had a rough winter because of the cold and one appears to be rotten at the top, the one trunk. The other has 3 heads, one of which is rotten. They are both putting out lots of pups on the trunks If the plants are not totally dead, is there any way to save them. They are over 20 years old and the trunks are at least 4 feet tall. Any advice would be appreciated.