Absolutely. I would definitely agree that they are invasive upon reading up on them more since starting this post- but perhaps only in certain regions/ climates. I did read some articles, from places like the Pacific Northwest, and down in Louisiana, and it does seem to be quite a big problem in those areas. Fortunately, it would seem that for some reason, the climate here in Western North Carolina might be preventing them from growing so vigorously. Maybe its just a hair too cold or too hot here for them to really take off, maybe both, or perhaps its the inconsistent rain we sometimes get. They seem in this area at least, to behave as daffodils and be pretty slow growing. That said, I would strongly recommend that anyone who wishes to have these, be sure to take care that they don't go to seed, and are in a contained location, and closely monitored. Invasive plants are no joke and can be quite a danger to a natural environment. Lest we forget the ever present Kudzu and Bottomland Privet to name a few.