Convulvulus sabatius

Near Minehead there's a house where the whole front wall is covered in blue from now until late autumn - every year! I was determined to track down this plant, and found it at Holbrook Garden last year. I planted 5 of them in my double wall this spring and am hoping that they will survive the winter. We are not quite as sheltered as Minehead, so there is a doubt, but we shall see! Lovely, though, aren't they! I don't know whether I could take cuttings - do you?