California Lilacs
What are they?
Plants in the genus Ceanothus are members of the buckthorn family (Rhamnaceae) and, because most species come from western North America, they are often known as California Lilacs. Other English names used in North America include mountain lilac and buckbush.
Where are they found?
Though they are native to most of North America, the bulk of the species come from the Rocky Mountains, westwards to the Pacific Coast of North America. In the UK, these are very popular garden plants, where they grow very well, but they do not seem to thrive away from the protection often afforded by garden cultivation and these plants are rarely recorded outside of cultivation.
Identification
California Lilacs are very distinctive as a group with their stiff evergreen leaves and often intense blue flowers (though there are some deciduous species and some with pink or white flowers). Identifying plantss can be very difficult as there is very little, reliable, information on identifying the plants found readily in cultivation. Books that cover identification with keys ofteen only cover true species, but most plants in cultivation are hybrids or selected sports which may not key out sucessfully. The species included here are those that I have found in amenity areas in the East Anglia region and which I have been able to work out an identification for. Other forms are doubtless out there! The colour of the flowers is often useful, otherwise, it's largely down to details of the current year's stems (especially dtails of any hairs present) and fine details of the leaves, including overall shape and details of any marginal teeth, hairs or glands present.
Ceanothus 'Concha'
Introduced as a garden ornamental. Flowers May to June. An evergreen shrub to around 3m in height. Leaves rather narrow, deep glossy green above, paler below, 3-4cm long. Flowers rich blue, often reddish tinged in bud.
I have seen Ceanothus 'Concha' listed as a variety of C. azureus. However, that name is not valid botanically and has been applied in the past to both C. caeruleus and C. tomentosus. Since 'Concha' does not closely resemble either of these species, it is more likely that it is a hybrid of horticultural origin.
 |
 |
|
 |
| |
|
|
|
 |
 |
 |
 |
| |
|
|
|
Ceanothus 'Dark Star'
Introduced as a garden ornamental. Flowers May to June. An evergreen shrub to around 3m in height. Leaves small, 1.5-2cm long, stiffly evergreen and with glandular teeth. Flowers rich deep blue, often reddish tinged in bud and appearing blue-purple from a distance. One of the most intensely coloured of garden shrubs.
Probably a hybrid between C. impressus and C. papillosus var. roweanus, having the leaf shape rather like that of the former and the thickly downy stems of the latter.
 |
|
 |
|
| |
|
|
|
 |
 |
 |
 |
| |
|
|
|