Dear Uli: When we take Dahlia imperialis cuttings, we use a 6-12" section of cane and remove the leaves. It is placed horizontally on a flat of potting soil and pressed in lightly. Usually 4-6 weeks is necessary to have a new plant. Regarding ledbourias, these can be rooted from leaf cuttings, similar to some begonias and african violets. This is a great way to rapidly increase these. Tony Avent Plant Delights Nursery @ Juniper Level Botanic Garden 9241 Sauls Road Raleigh, NC 27603 USA Minimum Winter Temps 0-5 F Maximum Summer Temps 95-105F USDA Hardiness Zone 7b email tony@plantdelights.com website http://www.plantdel.com/ phone 919 772-4794 fax 919 772-4752 "I consider every plant hardy until I have killed it myself...at least three times" - Avent