Mahonia fremontii - (Torr.)Fedde.

(Torr.)Fedde.

Mahonia, Fremont's mahonia

Berberidaceae Edible: Fruit Potential hazards — see below

gbif· cc-by

Deaver Herbarium

gbif· cc-by

Deaver Herbarium

gbif· cc-by-nc

Brigham Young University

Description

Mahonia fremontii is an evergreen Shrub growing to 2.5 m (8ft) by 2 m (6ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 8. It is in leaf all year, in flower from April to May. The species is hermaphrodite (has both male and female organs) and is pollinated by Bees. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: neutral and basic (mildly alkaline) soils and can grow in very alkaline soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

Edible Uses

Fruit - raw or cooked. It is usually cooked. An acid flavour but it is rather nice raw, especially when added to muesli or porridge. Unfortunately, there is relatively little flesh and a lot of seeds. A beverage has been made from the fruit. The ovoid fruit is about 15mm long. All varieties produce edible fruits, although quality varies. The moist-fruited form offers sweet, grape-strawberry flavor with mild acidity and minimal bitterness, while the dry-fruited form yields papery, tart berries with little flesh. In both cases, the berries are highly seedy, but edible raw or cooked. Edibility rating: 4 / 5) for moist-fruited forms; (2 / 5) for dry-fruited forms. Taste, Processing & Kitchen Notes: Fresh, ripe berries from moist-fruited plants are juicy and sweet, with a pleasant balance of acidity reminiscent of strawberries or red grapes. The seeds are small and firm but chewable. These berries make excellent preserves, jellies, syrups, or fruit leathers. For fruit bars, it’s best to deseed by mashing and straining before drying the pulp. Dry-fruited forms have papery skins surrounding seeds with minimal pulp. When boiled, they soften slightly, releasing a tart juice suitable for sweetened syrups. Even dry fruits yield flavorful results when simmered with sugar or honey. Because barberry fruits attract insects, always inspect for larvae before processing. Harvest & Processing Workflow: Harvest ripe berries in mid- to late summer when fully colored and slightly soft. Clip fruit clusters with scissors to avoid damaging spiny branches. Sort and wash the berries to remove insects. Fruits can be sun-dried for fruit leathers or boiled for syrup or jelly. To make syrup, simmer berries in water for 20 minutes, strain through muslin, sweeten, and reduce to desired thickness. Cultivar / Selection Notes: While no formal cultivars exist, horticultural selections of Fremont’s barberry emphasize fruit size, leaf color intensity, and berry abundance. Some cultivated forms used for ornamental purposes are derived from the moist-fruited populations, valued for their flavor and vivid color. Look-Alikes & Confusion Risks: May be mistaken for Red Barberry (B. haematocarpa), which has smaller, redder fruits and more numerous leaflets (5–9) with slightly narrower shape. Fremont’s barberry tends to have thicker, balloon-like fruits and leaves with a bluish cast. The two species often hybridize, creating intermediate forms. Traditional / Indigenous Use Summary: Fremont’s barberry was widely used by Native American tribes of Arizona and Utah. The berries were eaten fresh, dried, or cooked into preserves, while the roots and bark were used medicinally for stomach ailments and as a yellow dye. Some tribes pit-roasted roots for flavor or used them as a bitter tonic. The Hopi and Navajo are both known to have utilized the fruits in various forms.

Medicinal Uses

Antibacterial Antitumor Bitter Dysentery Hepatic Laxative Tonic. The plant has been used as an aid for the gums. The roots are bitter tonic, hepatic and laxative. An infusion has been used to promote digestion. Berberine, universally present in rhizomes of Mahonia species, has marked antibacterial effects and is used as a bitter tonic. Since it is not appreciably absorbed by the body, it is used orally in the treatment of various enteric infections, especially bacterial dysentery. It should not be used with Glycyrrhiza species (Liquorice) because this nullifies the effects of the berberine. Berberine has also shown antitumour activity. The root and root bark are best harvested in the autumn.

Known Hazards

The fruits are safe to consume, but stems, bark, and roots contain berberine, a powerful alkaloid with antimicrobial and physiological effects. These parts should not be ingested or used medicinally without professional oversight. As with all Berberis species, excessive consumption may cause mild stomach upset in sensitive individuals.

Distribution

South-western N. America.

Where It Grows

NORTHERN AMERICA: United States (Colorado (southwest), New Mexico, Arizona, California (south), Nevada (southeast), Utah (south))

Cultivation

Adapted to arid and semi-arid climates, this shrub thrives in gravelly or rocky loams and alkaline soils, tolerating both heat and drought. It performs best in full sun to partial shade and endures summer highs exceeding 40°C (104°F). Once established, Fremont’s barberry requires minimal water and is highly drought-resistant.. Unlike most members of this genus, this species requires a dry, perfectly drained position in full sun, a gritty slightly acid soil is best. It grows best on a sunny south facing wall in Britain and does well in a hot, dry position. It requires a position sheltered from strong or cold winds. Plants are only hardy in the milder areas of the country, tolerating temperatures down to about -10°c. Plants are slow-growing. Hybridizes freely with other members of this genus. The flowers are refreshingly fragrant. Some named forms have been developed for their ornamental value. This species is often confused with M. trifoliolata, which differs in only ever having 3 leaflets per leaf. dentification & Habit: This shrub typically reaches 1–3 m (3–10 ft) in height and is evergreen, though older leaves may drop in summer droughts. The stems are erect and multi-branched, often forming dense clumps. The inner wood and roots are deep yellow, reflecting the presence of berberine. The leaves are pinnately compound, consisting of 5–9 stiff, oval leaflets, each with sharp spines along the margins. The leaf surfaces are thick and glaucous (bluish wax-coated), reducing water loss in desert conditions. The flowers appear in small clusters of 3–8 bright yellow blossoms from April to June. Each flower is about 1 cm wide, with six petals and six sepals that appear similar. These are followed by rounded to elongate berries ranging from yellow and orange to red or purple depending on ripeness and subspecies. The berries measure 12–18 mm in diameter, larger than those of B. fendleri, and can be dry or juicy depending on genetic variation and environmental moisture. Seasonality (Phenology): Fremont’s barberry blooms in spring (April–June), often in synchrony with desert wildflowers and early pollinators. Fruits ripen in mid- to late summer, typically by July or August, though in high elevations they may persist into September. The evergreen foliage remains through winter, taking on a more bluish or purple hue in cold weather.

Propagation

Seed - best sown as soon as it is ripe in a greenhouse. It usually germinates in the spring. 'Green' seed (harvested when the embryo has fully developed but before the seed case has dried) should be sown as soon as it is harvested and germinates within 6 weeks. Stored seed should be sown as soon as possible in late winter or spring. 3 weeks cold stratification will improve its germination, which should take place in 3 - 6 months at 10°c. Prick out the seedlings when they are large enough to handle and grow them on in the greenhouse for at least their first winter. Plant them out in late spring or early summer and consider giving them some protection from the cold for their next winter. Division of suckers in spring. Whilst they can be placed direct into their permanent positions, better results are achieved if they are potted up and placed in a frame until established. Leaf cuttings in the autumn.

Other Uses

DyeA yellow dye has been obtained from the roots. A purple dye has been obtained from the fruit. Ecology & Wildlife: lowers are an early-season nectar source for bees, butterflies, and native wasps. Birds and mammals, including foxes and rodents, eat the berries and disperse the seeds. The dense, spiny branches provide excellent cover and nesting habitat. Fremont’s barberry is a keystone species in arid woodland ecotones, stabilizing soil and supporting insect biodiversity.