1 Salvia nemorosa 'Caradonna’ from the mildly aromatic silvery green leaves to the violet flower spikes with purple stems. Bees love the flowers that stay looking sharp long after the petals fall, thanks to papery bracts that hold their colour. Dead-heading – either little and often or in one go – encourages new flowering side-shoots till October. 'Caradonna’ loves sun; use it as a purple ribbon through late season grasses or, at 18in (45cm), it is the perfect centrepiece for a pot.
CALIFORINIA LILAC (Ceanothus ‘Victoria’) Evergreen bush (6ft tall by 4ft wide), SUN, drought tolerant This selection is simply the hardiest of the California lilacs available and the most reliable for our climate. The brilliant bright indigo blue flowers are an absolute show stopper in the spring and look great against the shiny and dark evergreen foliage. This tough shrub is extremely drought tolerant once established and is a fast grower and will quickly fill an empty space.
http://www.llifle.com/Encyclopedia/SUCCULENTS/Family/Asteraceae/18205/Senecio_mandraliscae Commonly called Blue Chalk Sticks, Blue finger, Bluefinger. It tolerates below-freezing cold to very high heat.