California Lilac at the Oregon Gardens (a bit of irony) as this was taken at the Oregon Gardens in Silverton, Oregon.
Commonly called the 'California Lilac', the ceanothus is unquestionably one of the best blue flowering shrubs available for garden use.
Here in the Pacific Northwest this plant is literally covered with blue flowers in late spring and early summer. Flowers do vary in different shades of blue, depending upon the variety chosen.
Native to Oregon - if you have ever traveled through southern Oregon or Northern California in June or early July you have probably noticed that the foothills are covered with a coat of blue. The plant is ceanothus thyrsiflorus. Its height is greatly determined by the care it receives, varying from five to fifteen feet in this region. The flowers also vary from light to deep blue.