Caroline Harbouri has written an interesting article about this in the latest issue of The Mediterranean Garden, number 65. Among several really good suggestions, she includes that favourite Ipomoea tricolor 'Heavenly Blue'. It does come well from seed. We find five or six plants growing together in a deepish 25cm (10 inch) pot don't grow too vigorously, even with daily watering; the plants shown flowering here were on a fence only a few feet high.