On the other hand, even in zone 4 I have seen triphyllums that are barely under the surface of the compost in the woods. In fact most of them are very near the surface. Carlo Carlo A. Balistrieri, J.D. Email: CABalist at facstaff.wisc.edu P.O. Box 327 Ashippun, WI 53003-0327 U.S.A. Voice: 414.569.1902 Telefax: same number, please call ahead.