Russ, Many thanks for your kind advice. One major problem with hunting this weed regularly is that it has important size variations. The tiniest specimens will hardly measure more than 1cm. They will produce just one or two flowers and a few seeds, enough to generate 5 to 10 descendants. These invisible specimens will always escape the gardener's hunt. But you are also correct : there is no other choice than performing a systematic tracking in order to keep the problem under control. *Dr. Christian M. Lachaud, PhD* _________________ http://www.saffron-crocuses.com/