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Blueblossom Ceanothus
Ceanothus thyrsiflorus
About Blueblossom Ceanothus (Ceanothus thyrsiflorus) Nurseries Show All Photos Blueblossom or Blue blossom Ceanothus is one of the most popular species of Ceanothus in landscaping applications. It varies dramatically in form and size over its natural range, with some plants growing fairly upright to 30 feet and others growing in a mounding form to only 2-3 feet tall. Blueblossom Ceanothus is evergreen, with leaves range from bright green to dark green. It has small flowers that are produced in a dense, puff-shaped clusters, that are white, light blue, dark blue or purple. They bloom in the winter or spring, and then mature into a dry, three-lobed seed capsule. Its flowers are important for bees and butterflies, and its seed pods are an important food source for birds and small mammals. Blueblossom grows in full sun or part shade. In the hotter, inland part of its range, it does better with more shade, on northern slopes, and if closer to an irrigated or a naturally moister area. In the cooler coastal part of its range, it prefers more sun and can tolerate drier locations. In general, if you water mature Ceanothus in the summer, they will usually be short-lived. Best to choose a Ceanothus native to your location, and stop direct watering after 1-2 years. There are two recognized varieties in the wild, Ceanothus thyrsiflorus var. thyrsiflorus and Ceanothus thyrsiflorus var. griseus (formerly considered a separate species).

Popular nursery varietals of Ceanothus thyroflorus are:
- Arroyo de la Cruz, which grows to 4 feet tall and 8 feet wide in a dense form, has small leaves, blue flowers and grows fast. It was taken from cuttings from a plant in San Luis Obispo
- Skylark, which grows to 5 feet tall and 5 feet wide in a compact form, has dark green leaves, profuse dark blue flowers, and has a long flowering season. It was cloned from cuttings from a plant in Mendecino.
- Snow Flurry, which can reach huge sizes, grows quickly up to 30 feet tall and 30 feet wide, with shiny dark green leaves and profuse white flowers. It was cloned from cuttings from a plant in Monterey
- Creeping Blueblossom, which grows slowly to 2-3 feet high, and up to 15 feet in diameter. It has a dense, mounding form, small, glossy, dark green leaves and light blue flowers. It is native in northern and central California, and southern California down to Santa Barbara.

Tolerant of recycled water.
Plant Description
Plant Type

Max. Height
2 - 30 ft (0.6 - 9.1 m)

Max. Width
2 - 40 ft (0.6 - 12.2 m)

Mounding, Spreading, Upright Columnar, Weeping

Fragrant - Pleasant, Slight

Growth Rate
Fast, Moderate


Flower Color
Blue, White, Green

Flowering Season
Spring, Winter

Native Status

Natural Setting
Site Type
Chaparral, redwood forest, and mixed woodland slopes and canyons below 2,000 ft. primarily along the coast and foothills of the Coast Ranges from Del Norte County to Monterey County, with scattered locations south and inland

Part Shade

Elevation ?
3' - 6180'

Annual Precip. ?
6.3" - 123.6"

Summer Precip. ?
0.17" - 3.72"

Coldest Month ?
36.6° F - 54.4° F

Hottest Month ?
56.0° F - 78.8° F

Humidity ?
0.01 vpd - 29.51 vpd

Soil Description
Reported to tolerate clay and sand, but Ceanothus generally do best in well drained soil. Do not fertilize or amend.

Soil PH
5.0 - 7.0

Fast, Medium, Slow

Cold Tolerance(° F)
Tolerates cold to 15° F

Sunset Zones ?
6, 7, 8, 9, 14*, 15*, 16*, 17*, 19, 20*, 21*, 22*, 23*, 24*

Companion Plants
Flannelbush (Fremontodendron spp.), Bush Poppy (Dendromecon rigida), Manzanitas (Arctostaphylos spp.), Coast Buckwheat (Eriogonum latifolium), Golden Yarrow (Eriophyllum confertiflorum), Sticky Monkeyflower (Mimulus aurantiacus), and various Rhus and Ribes species

Wildlife Attracted
Insects, especially bees and butterflies, are attracted to the flowers. Plants in the Ceanothus genus are host plants to the Spring Azure, Echo Blue, Pacuvius Duskywing, California Tortoiseshell, Pale Swallowtail, and Hedgerow Hairstreak butterflies.

Landscaping Information
Ease of Care
Moderately Easy

Water Requirement ?
Extremely Low
Very Low
Moderate - High

Very Popular

Max. Summer Water ?
No Summer Water, 1x/month
No Summer Water
Keep moist

Organic with Rocks

Tip pruning helps maintain a compact shape. Larger shrubs benefit from removal of leafless interior branches to open up structure and encourage new growth. Pruning is best done in dry season to prevent infection.

Propagation ?
For propagating by seed: Hot water and 2-3 mos. stratification.

Common uses
Groundcovers, Hedges, Bank Stabilization, Bird Gardens, Butterfly Gardens, Bee Gardens

Nursery Availability
Commonly Available

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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