Blue Myrtle CactusBlue Myrtle Cactus Pilosocereus azureus That colour is not a trick of the light. The Blue Myrtle Cactus is naturally coated in a waxy, powdery bloom that gives its tall columns a frosted, blue grey appearance that's quite unlike anything else you can grow on a windowsill. As it matures, golden yellow spines emerge along each ridge, warm against all that cool blue. Native to Brazil, Pilosocereus azureus grows in open, sun baked landscapes, which tells