mountain whitethorn

Ceanothus cordulatus

Family: Rhamnaceae.

Type: Small to prostrate evergreen shrub.

Branching: Alternate.

Leaves: Small gray-blue leaves. Its leaves have three prominent veins, as with other Ceanothus such as deerbrush.

Twig: Very pale, often ending in a white thorn (thus its name).

Fruit & Flower: Inflorescences are white, leading to small clustered drupes.

Miscellaneous: Like deerbrush and other Ceanothus, mountain whitethorn is associated with nitrogen-fixing bacteria, so it is a rapid colonizer and a facilitator of other species. It is shade-intolerant. It is the upper montane analogue of the deerbrush; the fact that it is evergreen, while deerbrush is deciduous, is interesting. At high altitudes, dropping leaves is too wasteful; plants simply must be evergreen to survive. In order to make this strategy work, plants such as mountain whitethorn and pinemat manzanita grow close to the ground, where they are more insulated from low winter temperatures.