Rhamnus alaternus
Italian buckhorn
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Family: Rhamnaceae · Type: Shrub · Not Native
Conservation status: Cal-IPC Yes
Rhamnus alaternus (Italian buckhorn) is a non-native California shrub in the Rhamnaceae family, recognized by non-native status, larger serrate leaves, and brown bark.
Italian buckhorn is a naturalized shrub found in coastal California regions including Monterey County, San Francisco Bay Area, and southern California coastal areas, occasionally appearing as a garden escape at sea level. Flowering details are not specified in the source data, so this part of the description cannot be completed. Growing as a compact evergreen shrub less than 6 meters tall with brown bark and puberulent branches, it develops dense, thick foliage. Its leaves are elliptic to lance-ovate, 20 to 60 millimeters long, with thick, glossy surfaces and prominently veined undersides, featuring unequally serrated margins. The plant produces small black fruits approximately 6 millimeters long, containing three stones.
Identification and appearance
Key characters: 2 sympatric species; distinguished by non-native status, larger serrate leaves, and brown bark
Habitat and range
Habitat: Occasional garden escape
Elevation: 0 m
Outside California: Mediterranean region, introduced New Zealand
Conservation status
Cal-IPC Yes
How to tell it apart
vs Ceanothus: Rhamnus has tiny inconspicuous flowers; Ceanothus has showy white or blue flower clusters.; vs Quercus: Rhamnus has thin leaves and berry fruits; Quercus has thick leaves and acorns.; vs Prunus: Rhamnus fruits have 2-4 stones inside; Prunus has single large stone (pit).; vs Rhus: Rhamnus has simple leaves and scaly buds; Rhus has compound leaves and hairy fruits.; vs Frangula: Rhamnus buds have protective scales; Frangula buds are completely naked.
Frequently asked questions
Is Rhamnus alaternus native to California?
No. Rhamnus alaternus is not native to California (recorded as not native).
What plant family does Rhamnus alaternus belong to?
Rhamnus alaternus is in the Rhamnaceae family, genus Rhamnus.
Is Rhamnus alaternus invasive in California?
Rhamnus alaternus is listed by Cal-IPC with an invasiveness rating of Yes.
What habitat does Rhamnus alaternus grow in?
Rhamnus alaternus grows in Occasional garden escape.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.