Hi Jan, We either use herbicides or we would have to surrender to the weeds. We have 5 acres (2 hectares) to care for, and it takes 4 high school or college students to keep the weeds down in summer, even with some use of herbicides. The Lycoris we grow are already in leaf when we start applying herbicides in early May. We will have to be more careful around the Hosta and the Lycoris in future. We do not use them as pre-emergent agents, but rather spray the weeds in leaf. We did not spray at all once the Lycoris scapes started to appear at the surface of the soil. Still, some could have gone into the soil earlier. Regards, Jim Shields ************************************************* Jim Shields USDA Zone 5 Shields Gardens, Ltd. P.O. Box 92 WWW: http://www.shieldsgardens.com/ Westfield, Indiana 46074, USA Tel. ++1-317-867-3344 or toll-free 1-866-449-3344 in USA