Hansen's Northwest Native Plant Database

Ceanothus thyrsiflorus (Blueblossom, California Lilac)


 Plantae – Plants


 Tracheobionta – Vascular plants


 Spermatophyta – Seed plants


 Magnoliophyta – Flowering plants


 Magnoliopsida – Dicotyledons






 Rhamnaceae – Buckthorn family


 Ceanothus L. – ceanothus


 Ceanothus thyrsiflorus Eschsch. – blueblossom

Truly blue flowers are hard to find--a fact all gardeners know well. Most of us have tried "blue" cultivars of many types of shrubs and perennials only to be disappointed once again with another lavender bloom. Yet we have only to turn to nature to find a shrub with flowers so blue they seem almost to vibrate in the bright sun. No hybridized bloom can compare with the northwest native Ceanothus thyrsiflorus, commonly called Blueblossom. 

It is an awesome sight to get right up close to these beautiful shrubs. In full bloom, Blueblossoms are a living Van Gough Painting! (But beware of black bees with yellow bands around their middles!) If you're fond of honeybees and bumbles and hummingbirds or if true blue is your favorite color, consider adding a Blueblossom (Ceanothus thyrsiflorus) to your landscape.

This is the "blooming-est" bush of the northwest ceanothus. Starting about a week or so mid-May and continuing for a solid month, the Blueblossom dons a coat of thumb-size blue flower clusters made of tiny little blue blossoms. Just before they open, the buds are a sort of pinky lavender color. Then they explode into beautiful densely packed fleurets that decorate the whole shrub.

  • At maturity, the average Blueblossom will reach 6 to 10 feet tall with a 5 or 6 foot spread. They can be trimmed into compact round cushions or left alone to form their nice natural shape.

  • The evergreen leaves are deep glossy green, very small in size and quite sturdy. The closely arrayed leaves provide good protection for small birds, keeping them hidden from predators.

  • A few weeks after blooming, the flowers will be gone and the small shiny green leaves will absorb some of the heat from the pavement, cooling the air through the hot summertime. They'll keep that green, tidy appearance during winter, even if we get snow as we sometimes do.

We highly recommend this all-star native shrub for all gardens whether large or small, city or country. It thrives in sun or shade and require minimal care. I've never watered mine. It grows beneath a huge Doug Fir and blooms its little heart out every year. The only thing Blueblossom lacks is strong fragrance but with all that beautiful blue, the lack of aroma is rarely noticed.

This is the rose garden Wally created for Audrey. It was a source of pride for him, checked it

 every day (in the morning, I think) to be sure it was perfect for his beloved.

He added the Ceanothus thysiflorus for contrast with the roses, and to protect them from the deer that came through the forest at the edge of the yard. I guess, though the roses were delectable, he thought the shrub would mask their scent. He also kept an old apple tree in the back for their dining pleasure. 

Next spring the cheerful green leaves will be fresh and delightful when the deciduous trees beh.ind them are still bare.

And early in the summer the small clusters of tiny true blue flowers will come again.

Neither the glossy leaves nor the abundant flowers will make a mess for the gardener to tidy. The evergreen leaves stay where they are and the tiny flowers fall as individuals, forming a thin blue haze beneath the shrubs until the slightest gust of wind blows them away.

The queen of wild evergreen lilacs, Blueblossom reigns with grace and majesty from southwestern Oregon to southern California (USDA zones 8-10).

The flowers resemble the top of the “thyrsus” - the staff of Dionysus, that unruly Greek God of wine.

This particular variety is a selected compact form which grows rapidly to about 6’ tall and 5’ wide - ideal for gardens close to buildings.

It is covered with bright, evergreen leaves and beautiful, deep lilac blue flowers in the spring which are intense--vibrant!

Blueblossom does well in sun or shade and requires minimum care or water.

Blueblossom is a must for west side gardens.

For a short comparison of northwest native ceanothus, click here.


Photo, left, credit:  Miguel Vieira - Flickr: Blue blossom ceanothus on Point Reyes Fire Lane Trail; Photo, center, credit: Salix; Photo, right, credit:  Hedwig Storch, Madeira, Palheiro Gardens

As I passed through a local neighborhood the other day I spied the scene here, the entrance to a small cul-de-sac. What an intriguing, inviting sight!

The Blueblossom (Ceanothus thyrsiflorus) were in full bloom this bright sunshiny morning. The curve of the road beckons the visitor to come in. Don't you want to see what's around the bend?

I drove to the top, and it was just as lovely from there.

The warm welcome of these evergreen NW native shrubs will be as gracious all year as it is now.


Photo, center, credit: Cc80804

Snow storm? No problem.

The map above shows the native region of this outstanding evergreen shrub. 

Photos We Share!

It is our pleasure to share the photographs in this section with you under the Creative Commons License (see link below for details). We retain ownership of the photos but you may use them freely as long as you credit our website for them.

Creative Commons License
These photos by http://www.nwplants.com are licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Contact:  nwplants@gmail.com ~ Copyright 2016 © The Wild Garden: Hansen’s Northwest Native Plant Database  ~ All rights reserved