The U.S. Dept of Agriculture's Natural Resources Conservation Service lists Ornithogalum umbellatum as a noxious weed in two States & considered invasive by four authoritive sources. See: http://plants.usda.gov/java/profile/?symbol=ORUM Whereas, O. nutans is not listed by that Service as either. Their distribution map over the USA should give you and idea of invasiveness in your part of Canada, Diane. Geoff Northern Rivers of NSW, AU