I have an S. leucophylla 'Tarnok' which had some major problems early this year. It came in with a bad aphid infestation, which went on into complete rhizome rot. There's nothing left above ground but a black husk, but I've checked the pot throughout the summer, and all of the underground roots are still firm and white, three months later. I was wondering if anyone had a technique for coaxing these roots into putting out some new leaves. So far, they don't seem to be doing much but staying alive. Thanks in advance.