Oxytropis gracilis is a charming Canadian native flowering now. It appears to prefer a dry spot and seems easily grown.
Pasithea caerulea has grasslike leaves and comes from Chile. It grows to about 60cm and seems to be tolerant of drought.
Sophora davidii is a deciduous shrub from south west China. It forms a neat rather prickly mound and has blue and white pea flowers in late May and June.
It is a robust evergreen climber growing here on a south facing, but exposed wall. It was unharmed by the winter of 2010. The scented flowers appear in May followed by, apparently, edible fruit. So far I have not been hungry enough, or brave enough to try them.