A Plant for All Seasons
Creeping mahonia flowers in spring along with tulips and daffodils.
During the winter months, Oregon grape hollies are stars of the garden.
Slightly fragrant bright yellow flowers are packed together.
To increase bushiness, cut back stems by 1/4 after flowering.
Creeping mahonia have modest but colourful flower clusters.
'Charity' in January.
Fruit from a Charity mahonia resemble grape clusters.
At Dart's Hill, Surrey, BC., mahonias are left to naturalize as nature intended.
Their holly-like foliage have sharp spikes along leaf margins.
A Bealei mahonia (M. japonica) flowers in February, VanDusen Botanical Gardens. Click on the pic for more.
Foliage tends to turn red and purple in full sun.
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Common Name: Oregon Grape Holly
Botanical Name: Mahonia aquifolium Form: upright, broad, spreading Family: Berberidaceae Genus: Mahonia Species: aquifolium Plant Type: broadleaf evergreen shrubs Mature Size: 3ft to 10ft x 5’ Growth: medium Origin: North & Central America, Asia, Himalayas Hardiness Zone: 5 to 9 Foliage: dark green to bronze, turn purple in winter in direct sun, 6x 2.5 cm, pinnately compound, lobed with sharp spine at lobe tips, stiff, leather-like Flowers: clusters (racemes) of fragrant yellow trumpet shaped flowers with 6 yelllow petals surrounded by 6 yellow sepals. Fruit: hanging clusters of blue edible berries Exposure: prefers shade to partial shade, but tolerates sun Soil: prefers moist, well-draining, acid soil, tolerates most soils, including wet ones Uses: screen, fillers, shade gardens, mixed borders, privacy hedge, attracts birds and butterflies Propagation: cuttings in summer into autumn Pruning: not necessary, but if needed do so in spring once the danger of frost has passed Problems: rust and powdery mildew but it’s not common Comments: Oregon grape hollies are used extensively by municipalities, landscapers and developers because of their versatility, toughness, winter interest, soil and shade tolerance and low maintenance. However, they are not as popular with maintenance crews because the spines on their holly-like foliage, which makes them painful to touch and to prune. Mahonia grape holly is also indigenous to the Pacific Northwest and is used in native and wildflower gardens. The popularity of mahonias is shared throughout the world, although they mostly originate from North America. They are easy to grow, and they look good all year long. Their attractive form, leaf colour and flowers stand out when other plants are dormant during the winter. Throughout the autumn through winter, the many clustered spikes of fragrant, bright yellow blossoms are framed by their deep green to purple leathery, holly-like foliage. It’s a lovely display, especially on grey days. The flowers also attract butterflies and birds. Their dangling clusters of purple berries resemble clusters of grapes, hence their common name. Although they are edible, they are tart therefore are often used to make jam. Please note that their active compound, berberine, is unsafe for pregnant, nursing women and children. The highest level of berberine is in the seeds, so remove them before making jam and consuming the berries. Wait for frost to harvest the berries for the best flavour. The berries attract juncos, towhees, waxwings, robins and other birds. Dyes are also made from the mahonia. The berries are used to make blue, purple, pink or green dye depending on the pH of the soil and water. The stems and roots also produce a yellow dye often used by indigenous peoples of the Pacific Northwest. Although mahonias are soil tolerant, they prefer moist, good draining soil and benefit greatly when mulched. Protect them from full sun and exposure to high winds. Pruning: Remove or cut back wayward stems to reshape plants in spring after the last frost. At the same time, deadhead, and prune out any diseased, damaged and dead stems. Remove old, non-productive as well as spindly branches. For leggy mahonias that just have growth at the top of bare stems, cut some or all of the branches back by ¼. After pruning water well and mulch. Propagate: Take cuttings in late summer into early autumn from healthy new growth from the current season. For more on semi-hardwood cuttings click on Taking Cuttings. Cultivars and varieties:
Red twig dogwood and creeping mahonia one grey January day.
Mature mahonias used as a screen while providing some 'bones' to the garden.
Mahonias are effective screens and impenetrable when used as barriers due to their spikey leaves.
The fruit is attractive and edible but take care preparing it.
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