Triteleia
When in flower the are reminiscent of Agapanthus, but actually related to Allium. Pretty trumpet-like blue, violet or yellow flowers, in a umbel, on a bare stems, as the foliage is dying down. Native to the west coast of North America, so adapting to a range of conditions, but our experience has been on well-drained soils, in full sun.
The sweetly scented flowers of Triteleia attract bees, butterflies and other pollinators, and their self-seeding habit can ensure a copious provision of nectar and pollen throughout the midsummer flowering period.