I have had these forget me nots at least ten years in my garden and I do not have to sew seeds every year. They are actually known as Brunnera Macrophylla, Siberian Bugloss or great forget-me-not. I got a couple of plants from someone I knew and now half the garden has them and they make a wonderful show in Spring. They remain where they are, tend to spread a bit and flower every year regularly. I love them. If they get the overhand you can pull them out, or plant them elsewhere.