Monday, May 23, 2011


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 above. 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.

Rockery Plants - Part 2

OK, here's Part 2 of our virtual plant identification tour of Seattle rockeries.
This is Bergenia crassifolia, or winter blooming bergenia. It is also called "pig squeak" because the leaves make a squeaking sound if you rub them when they are wet. This is an evergreen perennial that requires little care. Just cut away old or cold-damaged leaves and faded flowers to keep it tidy.

These chartreuse flower heads belong to Euphorbia (I'm guessing this is a young specimen of E. chariacias wulfenii) a large genus of plants that includes the poinsettia (E. pulcherrima). Be careful handling these plants. They have a milky, white sap that is very irritating to the skin - I always wear rubber gloves when working with them, having been burned (literally!) in the past.

Along with them, a collection of English bluebells have taken up residence. Rarely planted on purpose, you'll find these cheerful blue flowers in gardens and rockeries everywhere in Seattle.

Speaking of blue flowers, these are grape hyacinths (Muscari sp.) These also happily multiply wherever they are planted. The red plant below them is a variety of Sedum.

Of course, rockeries are not all planted with ground covers and small perennials. When the planting pockets are large enough, small trees and shrubs can do quite nicely. Here at the top of the rockery is a weeping Japanese maple (Acer palmatum 'Dissectum Atropurpureum'), below it is David's viburnum (Viburnum davidii), and at the bottom, lavender (Lavandula sp.) is blooming.

Rockery gardening can be challenging because the planting spaces are often quite small and they dry out quickly in warm weather. Watering can be difficult because the force of the water stream can wash away some of what little soil is there. But after some trial and error, you will find a planting combination that will thrive with a minimum of care.

Missed the first part of the tour?
Go back to Part 1.