I'm in the process of renovating a part of the bulb lawn. Near the street where people park weed-dispersing cars, it acquired an infestation of Geranium lucidum (shiny geranium) that could not be stopped except by killing the whole area. I'm thinking of applying the persistent pre-emergent Casoron now and having the area covered with a bark mulch, then waiting to see if the weed reappears next spring. If it doesn't, I'll replant with low shrubs and bulbs. Does anyone know how Casoron might affect bulbs planted about 14 months after application?