Updated: Nov 19, 2022
Ceanothus, also known as California wild lilac, is starting to bloom now in Seattle. Its striking, purple-blue flowers are shaped like tiny bottle brushes, thus inspiring the common name.
There are many varieties of Ceanothus, but few are hardy enough for our climate. Most are native to California where, after a wet winter like this past one, the coastal hills are covered in a blue haze of bloom in the spring.
The most common variety of Ceanothus grown in Seattle is the one shown above, Ceanothus impressus or Santa Barbara Ceanothus. If you add one to your garden, be sure to give it plenty of room - it can easily get 10 feet tall and 10-15 feet wide.
Flower color among the varieties can range from white (which is rare), through pale blue, to deep purple-blue. When choosing one for your garden, as always, buy plants in bloom to be sure of what you are getting.
Ceanothus plants are generally drought tolerant, needing a bit of supplemental watering the first couple of seasons while they get established.
There are a couple of Ceanothus ground covers that are grown in our area. Point Reyes (C. gloriosus) has glossy, dark green, holly-like leaves, with light blue flowers, and can get as tall as 18", with a spread (if it is happy) of 12 to 16 feet.
The most striking Ceanothus ground cover is 'Diamond Heights,' (C. griseus horizontalis 'Diamond Heights') shown at right. It does not look anything like its relatives until small, pale blue flowers appear in late spring. But flowers are not the reason to plant this beauty. You'll want this in your garden because of the foliage - those yellow-green leaves with splashes of dark green in the center are a joy to behold.
Unfortunately, we've had some very cold weather the past three or four winters and this ground cover has not fared well. My once-thriving 'Diamond Heights' specimens have all been killed by the cold. However, that doesn't mean you should give up on this plant. Just treat it as an annual, tuck it into containers and let it spill over the edges.