Family: Berberidaceae

Common name: Dull Oregon grape

E-flora BC: https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Mahonia%20nervosa

Wikipedia: https://en.wikipedia.org/wiki/Mahonia_nervosa

Dull Oregon grape has been known as Mahonia nervosa for a long time, but from a taxonomic standpoint, based on genetic evidence, it ought to be merged into the genus Berberis. This change has been adopted in the most recent edition of the Flora of the Pacific Northwest, 2nd edition (2018). Hence, the name (Berberis) on this site does not agree with the name (Mahonia) on E-flora BC and Wikipedia, as listed above.

Be aware that there are two Oregon grape species in our region; tall (B. aquifolium) and dull (B. nervosa). Typically, the height of these plants do differ, but this is not the best characteristic with which to distinguish them. Primarily, you need to look at leaf characteristics, and take into account where you encounter the plant, to arrive at a correct identification.

Here’s a summary of the differences between tall and dull Oregon grape:

  • Tall (B. aquifolium) is generally found in sunny exposed, often rocky, locations. Dull (B. nervosa) is generally an understory plant growing within the forest.
  • The compound leaves of tall Oregon grape have 5-11 leaflets. The compound leaves of Dull Oregon grape have 9-19 leaflets. These numbers overlap, but in general ‘tall’ has shorter leaves with fewer leaflets, and ‘dull’ have longer leaves with more leaflets per compound leaf.
  • The individual leaflets of tall Oregon grape are usually quite shiny, the leaflet blade is a bit buckled or warped. On dull Oregon grape, the leaflets are not particularly shiny and the individual leaflets are mostly flat.
  • Look at the underside of the leaf. If each leaflet has a single, very prominent, raised central vein, then you’re looking at tall Oregon grape. If each leaflet has several veins emanating from the base of the leaflet, then you’re looking at dull Oregon grape.

Let’s look at some photos of dull Oregon grape:

Dull Oregon grape in the understory of a forest. Note the long compound leaves with many (>15) leaflets per leaf. The leaves are not particularly shiny and the leaflets are quite flat compared to those of tall Oregon grape. Photo credit: Hitomi Kimura

More dull Oregon grape plants:

The underside of dull Oregon grape leaves show the ‘palmate’ veins – several veins emanating like fingers from the base of the leaflet. Perhaps the species epithet ‘nervosa’ refers to the multiple “nerves” visible on the underside of the leaflets. Photo credit: Hitomi Kimura

Dull Oregon grape flowers early in the spring, the flower cluster is more slender and contains fewer flowers than that of tall Oregon grape.

  • Dull Oregon grape flowers (both left and right photo) Photo credit: Douglas Fraser.
The edible berries of dull Oregon grape. The berries have a coating of ‘epicuticular’ waxes that give them a grey-ish hue. The waxes rub off easily, revealing the dark purple colour underneath – you may have observed the same phenomenon on store bought blueberries or dark grapes. Photo credit: Chaerea via Flickr

For a side-by-side comparison of dull and tall Oregon grape characteristics, please see the page for tall Oregon grape: (https://wordpress.viu.ca/biol223/berberis-mahonia-aquifolium/)