Carole, Is your Sisyrinchium striatum well behaved with you? Here in the UK it seeds itself around everywhere in our garden (we don't mind, as we let it form a sort of ground cover, and in places where we don't want it, it's very easy to pull out). S. macrocarpum, a much neater little plant with deeper-coloured leaves and more golden-yellow flowers, also seeds itself around here very freely. Alas, the equally neat blue-flowered S. bellum 'Californian Skies' has in its whole life with us produced only one single self-sown seedling, which was pretty true to type - I wish it was as prolific as its brasher relatives!