There were no flowers on mine the past summer, either, Richard. So I guess cold temperatures/late springs may discourage it too.
@DonDuck, you don't need to worry much, afaik, about cross pollination from walking onions. Perhaps because they are an inter-species cross (A cepa aggregatum x A fistulosum iirc), they don't produce viable seed very easily, and likely wouldn't cross too readily with wild onions at all, which would likely be some other third species. Not saying it is impossible, but not something you'd have to worry about.
And if they did produce a rare cross, it would be something very cool!
