Dear Frank and all, Well I guess I should have said they do self sow in that after seed falls, it germinates and develops, but without protection they do not survive winter. Sounds like you have enough mulch protection to keep them alive over that first winter. I bring new seedlings into a frost free area to insure survival. They are definitely a very hardy species, but I doubt you will find them spreading around the garden in Zone 5/6. What other hardy Crinum do you grow? Jim W. On Jul 19, 2013, at 4:24 PM, <email@example.com> <firstname.lastname@example.org> wrote: > I have to remove seed heads or else they will self sow. Kept under mulch in > winter. I can just dig up seedlings after a year or two. > Frank Cooper zone 5-6.