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Products > Ceanothus 'Cynthia Postan'
 
Ceanothus 'Cynthia Postan' - Cynthia Postan Ceanothus

San Marcos Growers has permanently closed as a business. This is an archived page preserved for informational use.  
Image of Ceanothus 'Cynthia Postan'
 
Habit and Cultural Information
Category: Shrub
Family: Rhamnaceae (Buckthorns)
Origin: California (U.S.A.)
California Native (Plant List): Yes
Evergreen: Yes
Flower Color: Blue
Bloomtime: Spring
Parentage: (C. papillosus v. roweanus x thyrsiflorus v. griseus)
Height: 6-8 feet
Width: 6-12 feet
Exposure: Full Sun
Irrigation (H2O Info): Low Water Needs
Winter Hardiness: 10-15° F
Ceanothus 'Cynthia Postan' (Cynthia Postan Ceanothus) - A dense shrub 6 to 8 feet tall and slightly wider with small, glossy, dark green leaves and violet blue flowers emerging from reddish buds in the late spring. The flowers can completely cover the plant at peak bloom. ‘Cynthia Postan’ is somewhat intermediate between two more commonly grown Ceanothus papillosus hybrids, Ceanothus 'Concha' and C. 'Wheeler Canyon'. It resembles 'Concha' more in form, although it is slower growing, and has flowers that are more aligned with those of 'Wheeler Canyon'.

Plant in full sun. Little irrigation required. Plants along the coast have demonstrated considerable tolerance of heavy soils. Hardy to 10° F.

We originally discovered this plant when investigating differences we had noted in plants being grown in the nursery trade labeled Ceanothus 'Wheeler Canyon.' We are thankful to Dave Fross at Native Sons Nursery for bringing this great cultivar to our attention. It was selected at the University Botanic Garden in Cambridge, England from seed collected by Lady Cynthia Postan from a plant of Ceanothus papillosus var. roweanus growing in the Regional Parks Botanic Garden in Berkeley, CA. We grw this plant from 2006 until 2012. The genus name comes from the Greek word keanthos which was used to describe a type of thistle and meaning a "thorny plant" or "spiny plant" and first used by Linnaeus in 1753 to describe New Jersey Tea, Ceanothus americanus

The information displayed on this page about Ceanothus 'Cynthia Postan' is based on our research conducted about this plant from books in our nursery library as well as from information that is provided by reliable online resources. We also have included our own observations made about it as it grew in the nursery gardens and other gardens visited, as well how the crops of this plant performed in the containers when we had them in our nursery field. We also include comments received from others and welcome hearing from anyone who has information about this plant, particularly if it includes cultural information aiding others to better grow it.

 
We closed for regular business at the end of 2025 in order for the property to be developed for affordable housing.
Our gates remain closed but we will open them by appointment to interested parties as we liquidate remaining supplies and equipment.
 
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