I havent tried schilleriana yet, but I have a guttata cross, and other than its brief winter rest, its pretty easy going. It gets full southern exposure, has winter temps in the 60's, summers in the 80's. It grows quite fast in the early summer and flowers as soon as the growth finishes up. When the roots arent actively growing, I keep it really dry, but when active it gets lots of frequent watering and fertilizer. I also use KLN to mist the leaves and roots to give the plant a boost. As long as the roots are happy, the plant is happy, so maybe try using KLN and a high Phosphorus fertilizer to coax it into making new roots? Good luck!!