| California lilac, Ceanothus impressus, Ceanothus arboreus, Ceanothus griseus, Rhamnaceae|
Ceanothus thyrsiflorus, known as blueblossom or blue blossom ceanothus, is an evergreen shrub in the genus Ceanothus that is endemic to California. The term 'Californian lilac' is also applied to this and other varieties of ceanothus, though it is not closely related to Syringa, the true lilac.
Ceanothus thyrsiflorus Wikipedia
C. thyrsiflorus can grow more than 6 m (20 ft) tall in its native chaparral habitat. Flowers vary from different shades of blue to close to white. It is popular with birds, butterflies, and other pollinators.
C. thyrsiflorus has been used in gardens extensively, and several cultivars have been selected. Popular garden varieties include:-'Blue Mound' which can grow to 1.5 m (4 ft 11 in) tall
'Cascade' which may reach 8 m (26 ft) of height
'El Dorado', a variegated cultivar with gold edge foliage and powder blue flowers
'Repens' which stays as a shrub around 1–3 m (3 ft 3 in–9 ft 10 in) tall
'Repens Victoria', forming a sturdy evergreen mound and most useful groundcover with powder blue flowers
'Skylark', a tall type with blue flowers (this cultivar has gained the Royal Horticultural Society's Award of Garden Merit)
'Snow Flurry', with white flowers
Ceanothus is derived from the Ancient Greek, κεάνωθος (keanōthos) 'spiny plant'. The name was originally used by Theophrastus for another plant, and Linnaeus reused it for Ceanothus.
Thyrsiflorus is derived from the Ancient Greek word, Thyrsus, meaning a 'contracted panicle', 'wreath', or 'thyrsus'. Florus is derived from Latin and means 'flower', and so thyrsiflorus means 'with flowers arranged in the shape of a contracted panicle or thyrsus staff'.