Pronounciation: Ber-BER-is a-qui-FOL-ee-um

Hardiness zones:
Sunset 8-24
USDA 7-11

Landscape Use: Landscape entryways, foundation and group plantings, natural light atriums, shaded courtyards and patio gardens. Oregon grape will grow in Phoenix and Tucson with western sun protection, but thrives as a landscape plant in higher elevation Arizona cities such as Prescott, Payson, Cottonwood, Sedona, Show Low, and even Flagstaff.

Form & Character: Stiff and upright, informal, rugged, interesting, oriental, rugged.

Growth Habit: Evergreen, woody, broadleaf perennial shrub, highly variable, very stiff, rigid and upright, 3- to 6-feet tall. Spreads very slowly by underground creeping rhizomes (like a Costa Rican sloth).

Foliage/Texture: Persistent leaves are alternate and pinnately compound, 6- to 12-inches long. Leaflets, arranged 5 to 9 per leaf, are 2- to 3-inches long, lanceolate, sometimes with undulating margins and sharply spined teeth along their margins, dark glossy green adaxial, thick, waxy cuticles, and pale green abaxial. Lateral leaflets are opposite and sessile, while the terminal leaflet has a petiole; each leaflet has a distinct midrib. The young foliage and new stems are somwtimes brightly colored red and purple. Winter foliage is reddened by cold weather. Oregon grape has a medium coarse texture.

Flowers & Fruits: Yellow flowers are monoecious, perfect, small, borne copiously on long, upright racemes, edible. Fruits are small 3/16-inch drupes, waxy green when immature and dark blue, edible (sour) when mature.

Seasonal Color: Yellow flowers in spring, berries in summer and fall.

Temperature: In Phoenix, Oregon grape like people and eggs suffer mightily when temperatures exceed 110^oF. Conversely, Oregon grape foliage turns a wonderful reddish color during winter when the weather is cold such as in Flagstaff, Arizona.

Light: Partial to full shade is imperative to successfully cultivating Oregon grape in Phoenix. This means absolutely NO western exposures.

Soil: Tolerant of all soil conditions except high alkalinity and salinity. Of special note, all Berberis species grow well in heavy clay soils.

Watering: Oregn grape needs regular supplemental water during the warmer months of the year (like June, July, and August when the sun is blazing hot in Phoenix).

Pruning: Oregon grape plants are pruned just like Nandina (heavenly bamboo) which means prune canes (stems) back (heading cuts) individually to different lengths as needed to promote a full canopy of leaves. One can even head back (prune) Oregon grape severely to the ground after bloom to reinvigorate growth.

Propagation: Seed, semi-hardwood shoot or root cutting, micropropagation (tissue culture), division of basal clumps much the same as Nandina domestica. I used to successfully propagate "Mahonia" plants in landscapes along the central California coast by direct sticking stem cuttings into the ground in a shaded garden spot during the later fall months.

Disease and Pests: In moist temperate climates, Oregon grape plants are predisposed to numerous leaf bacterial and fungal (rust, mildew) diseases as well as insects with rasping mouth parts. In drier climates (like southern California and Arizona, one would never know this as 'Mahonias' seem generally indestructable.

Additional comments: Oregon grape is an amazing plant that struggles with the extreme summer heat in Phoenix, ergo it needs some shade protection from the hot summer afternoon sun. There are many Oregon grape cultivars (such as 'Compactum' and 'Golden Abundance') and hybrids with Berberis pinnata (California grape), such as the named hybrid 'Ken Hartman'. My personal favorite is Berberis x 'Skylark' (a Oregon/California grape hybrid cross made by M. Nevin Smith in Watsonville, California). I first planted this 'ubber boss' hybrid cultivar during the early 1980s when I was a young dude landscape contractor in central California. It has mature leaves that are dark green with a highly polished surface, brilliant red to orange new leaves and stems and can become purple-tinted in response to winter cold.

Berberis biochemistry and uses: Both the roots and rhizomes of Oregon grape have been used medicinally for hundreds of years to treat infections because of their powerful antibiotic properties. The plant contains the alkaloids berberine and hydrastine. Berberine is highly bactericidal, amoeboidal and trypanocidal. Oregon Grape extracts were shown in one pharmacological study to reduce inflammation (often associated with psoriasis), and to stimulate the white blood cells known as macrophages. The roots are used in herbology as a nutritional aid to the digestive and circulatory systems. The fruit is an excellent gentle and safe laxative. A yellow dye is obtained from the inner bark (cortical region) of all stems and roots and dark green, violet and dark blue-purple dyes are obtained from the fruit. A green dye is obtained from the leaves.

More Berberis: Berberis repens (creeping barberry) is a creeping and spreading dwarf (to 1-foot tall, but generally less) that is native to montane and alpine regions of the western United States including Arizona. It is used along with Oregon grape as a landscape plant (sparse ground cover) in higher elevation Arizona landscapes in the Flagstaff, Prescott, Payson and the Show Low/Pinetop areas of eastern Arizona.