This has been a remarkable autumn for late or second flowering. I have always thought very highly of blue flowers which is I suspect why I was so attracted to Meconopsis. Some of those above are a deep true blue but many show just hint of purple. The Corydalis - a hybrid in my garden but derived from C. cashmeriana, the Ceonothus, the skullcap (this is a wonderful blue and was bought as an annual and grown from seed but has been perennial some some years - Salvia but not sure of species) and the Delphinium are blue as is the annual Lobelia but the Clematis heraclefolia, lavender, geranium and Veronica all have a touch of red which gives them a purple hue.