Blue Brush, Blueblossom
Ceanothus thyrsiflorus

Family: Rhamnaceae

What it is like

Bloom Color: Blue, Lavender. Main Bloom Time: Early spring, Late winter. Form: Prostrate, Spreading or horizontal.

Ceanothus thyrsiflorus is an evergreen Shrub growing to 4.5 m (14ft) by 4.5 m (14ft) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 7. It is in leaf all year, in flower from May to June, and the seeds ripen from August to October. The species is hermaphrodite (has both male and female organs). It can fix Nitrogen. Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil. The plant can tolerate maritime exposure.

Height (m): 4.5

Where it is found

Wooded slopes and canyons below 600 metres, often in the neighbourhood of streams, in evergreen forests in California.

South-western N. America - California to Oregon.

Conservation Status:

Countries/locations it is found in

How it is used

Food

Rating: 0

Medicine

Rating: 0

Other

Rating: 2

A green dye is obtained from the flowers. All parts of the plant are rich in saponins - when crushed and mixed with water they produce a good lather which is an effective and gentle soap. This soap is very good at removing dirt, though it does not remove oils very well. This means that when used on the skin it will not remove the natural body oils, but nor will it remove engine oil etc The flowers are a very good source, when used as a body soap they leave behind a pleasant perfume on the skin. The developing seed cases are also a very good source of saponins. The sub-species C. thyrsiflorus repens is a good ground cover plant for sunny positions, growing well on banks and reaching a height of 90cm. Plants can be grown as a hedge in exposed maritime areas though they do not succeed in the most exposed positions and can be slow to establish. Wood - close-grained, rather soft.

Dye: Plants that provide dyes.

Hedge: Plants that can be grown as hedges.

Soap: Plants used directly as a soap substitute.

Ground cover: Ground Cover

Hedge: Hedge

Nitrogen Fixer: Plants that fix nitrogen in the soil

How it is grown

Landscape Uses:Erosion control, Ground cover, Hedge, Massing. Prefers a warm sunny position but tolerates light shade. Tolerates some lime, but will not succeed on shallow chalk. Tolerant of maritime exposure. A very ornamental plant it is hardy to about -10°c. The sub-species C. thyrsiflorus repens. McMinn. is somewhat hardier, to about -15°c. There are several named forms selected for their ornamental value. A plant has reached 6 metres tall at Kew in an exposed position, but is damaged in severe winters. Plants dislike root disturbance, they should be planted out into their permanent positions whilst still small. A fast-growing plant, it flowers well when young. Dislikes heavy pruning, it is best not to cut out any wood thicker than a pencil. Plants flower on the previous year's growth, if any pruning is necessary it is best carried out immediately after flowering has finished. Constant pruning to keep a plant small can shorten its life. There are a number of named varieties developed for their ornamental value. Hybridizes freely with other members of this genus. Some members of this genus have a symbiotic relationship with certain soil micro-organisms, these form nodules on the roots of the plants and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby. Special Features:North American native, Attractive flowers or blooms.

Propagating it: Seed - best sown as soon as it is ripe in a cold frame. Stored seed should be pre-soaked for 12 hours in warm water and then given 1 - 3 months stratification at 1°c. Germination usually takes place within 1 - 2 months at 20°c. One report says that the seed is best given boiling water treatment, or heated in 4 times its volume of sand at 90 - 120°c for 4 - 5 minutes and then soaked in warm water for 12 hours before sowing it. The seed exhibits considerable longevity, when stored for 15 years in an air-tight dry container at 1 - 5°c it has shown little deterioration in viability. The seed is ejected from its capsule with some force when fully ripe, timing the collection of seed can be difficult because unless collected just prior to dehiscence the seed is difficult to extract and rarely germinates satisfactorily. Prick out the seedlings into individual pots as soon as they are large enough to handle. Grow them on in the greenhouse for at least their first winter and plant them out into their permanent positions in late spring or early summer. Cuttings of half-ripe wood, taken at a node, July/August in a frame. Cuttings of mature wood of the current year's growth, 7 - 12 cm with a heel, October in a cold frame. The roots are quite brittle and it is best to pot up the callused cuttings in spring, just before the roots break. Good percentage.

Best place to grow: Woodland Garden Sunny Edge; Ground Cover; Hedge;

Habit: Shrub

Hardiness: 7-9

Growth: Medium

Soil: Light (sandy), medium

Shade: Semi-shade, no shade

Moisture: Dry, moist

Things to keep in mind

Its other names

Local names

Synonyms

C. bicolor. C. elegans.