Mahonia

( muh - HOW - nee - uh )

At-A-Glance Information

This genus of evergreen shrubs includes species which have varying water and sunlight needs. Flowers will attract birds and butterflies to the garden. Flowers are yellow and borne in dense rounded or spiked clusters and are followed by sharply acidic powdery berries that can be blue, black, brown or red. Plant Mahonia shrubs in mixed beds to add texture and structure, or as backdrop plants in shaded areas. It also can be mass-planted on hillsides for erosion control, used in wildlife or native gardens, or as security or barrier hedges to keep out deer and humans. Leaves are spiny and the foliage can be prickly, so take care when planting these in your yard; keep them pruned back from play areas and walkways.

Mahonia Species and Varietals

The genus Mahonia includes about 70 species and is a member of the plant family Berberidaceae. The plants in this genus are related to Berberis (Barberry), Nandina (Heavenly Bamboo), Epimedium (Bishop's Hat), and Paxistima (Oregon Boxwood). The best growing zones for Mahonia vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Mahonia aquifolium (Oregon Grape, Holly-Leaved Barberry, Oregon Grapeholly)
This species, best in USDA hardiness zones 5-9 or Sunset growing zones 2-12 and 14-24, is native to British Columbia down to Northern California west of the Cascade Mountain Range. It is the state flower of Oregon and forms a dense, bushy shrub that reaches 6 feet tall and 5 feet wide. It spreads via underground stems. Leaves are glossy green, emerging bronze. In fall and winter, leaves will turn red to purple-bronze. Flowers bloom in early spring. Fruit is edible and blue-black and makes a great jelly. Great for screening or as a barrier plant. Performs best in warm climates when planted in shade, and needs little to regular water. This species is considered invasive across northeastern and midwestern North America and central Europe.

Mahonia fortunei (Chinese Mahonia, Fortune's Mahonia, Holly Grape, Ten Great Merits, 十大功劳)
This Chinese native grows well in USDA hardiness zones 7-10 or Sunset growing zones 5-9 and 14-24. Individual shrubs reach 6 feet tall and 3 feet wide. Leaves are a matte green above, yellow-green with a netted pattern underneath. Flowers appear in late fall in short clusters. Prefers full sun or light shade and regular waterings.

Mahonia fremontii (Desert Mahonia, Fremont's Mahonia, Fremont Barberry, Desert Oregon Grape)
This species grows well in USDA hardiness zones 5a-10a or Sunset growing zones 2b-24 and is native to Southwestern U.S. desert regions. Leaves are grey-green to yellow-green and have sharp spines. Flowers appear in late spring and berries that follow are dark blue to brown fruit. These plants prefer light shade to full sun and need little to no water to perform well in the landscape. 

Mahonia japonica (Japanese Mahonia, Hiemalis Mahonia, Oregon Grape-Holly, Southern China Mahonia, 华南十大功劳)
This species grows well in USDA hardiness zones 6-8 or Sunset growing zones 3b-12 and 14-24, and is native to China and Taiwan. It reaches 10-12 feet tall and 10 feet wide, with vertical stems and horizontal leaves that create an eye-catching pattern. Leaves are leathery and yellow-green on top, grey-green underneath, and have a small yellow patch towards the stem. Flowers appear in late winter, followed by berries that are blue and powdery. Needs rich soil amended with organic matter. It does best in partial shade in most climates, though in cool summer areas can take full sun. It prefers a regular watering schedule to thrive. This species is considered invasive in the southeastern United States (Maryland down through Florida and west to Texas).

Mahonia lomariifolia (Chinese Hollygrape, Chinese Mahonia, Burmese Mahonia, Yunnan Mahonia)
This species grows well in USDA hardiness zones 9a-9b or Sunset growing zones 6-9 and 14-24 and is native to southwest China, Taiwan, and northern Myanmar. They reach 6-12 feet tall and 6 feet wide and have erect stems. Leaves are deep green and appear clustered at the ends of branches. Yellow flowers bloom in the middle of wintertime, and are followed by blue berries. This species needs partial shade, especially in the higher temperatures of the late afternoon. Prefers regular waterings. This species is considered invasive in New South Wales, Australia, South Africa and New Zealand.
Mahonia x media (Berberis hortensis) (Oregon Grape, Grape Holly, Media Mahonia)
These sterile hybrid were created by crossing Mahonia lomariifolia with a Japanese species of Mahonia. Plants produce fragrant yellow flowers that bloom in fall and winter. Cultivars are listed and described below:
'Arthur Menzies'
10-12 feet tall and 8-10 feet wide.
'Buckland'
This species reaches 15 feet tall and 12 feet wide.
'Charity'
To 15 feet tall and 12 feet wide.
'Faith'
6-10 feet tall and 6 feet wide.
'Lionel Fortescue'
6 feet tall and wide.
'Winter Sun'
4-5 feet tall and just as wide.

Mahonia pinnata (California Holly Grape, Wavyleaf Barberry, Shinyleaf Mahonia, California Oregon Grape)
This species grows well in USDA hardiness zones 7a-10b or Sunset growing zones 4-9 and 14-24 and is native from southern areas in Oregon down to Southern California. Reaches 4-5 feet tall and just as wide. Leaves are somewhat crinkly and new growth is tinted red or orange. Flowers bloom in springtime, followed by dark blue powdery berries. Needs full sun in cooler areas and partial shade in warmer ones. No irrigation is needed once established. Cultivar 'Ken Hartman' has dense, uniform foliage.

​Mahonia repens (Creeping Mahonia, Creeping Oregon Grape, Creeping Holly Grape, Creeping Barberry)
This species is best in zones 2b-9 and 14-24. These shrubs are native from British Columbia to Northern California and eastward to the Rocky Mountains. Reaches a foot tall and three times as wide, with underground spreading stems. Great for winter color. Leaves are blue-green, turning bronze to pink in winter chill and mid to late spring flowers are followed by blue berries. This species makes a great groundcover and needs full sun to partial shade and little to no water.

Caring for Mahonia

Before planting Mahonia in the garden, consider installing a 18-24 inch deep root barrier around the planting area, leaving 1-2 inches of barrier above the soil to prevent roots from jumping over. Plant Mahonia in a space in the landscape that receives full sun to partial shade; ideally, they appreciate between 6 and 8 hours of sun each day, but can take some afternoon shade when temperatures are at their peak. When these shrubs are grown in lower light, they will not flower as profusely. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 5.0 and 8.0 (acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants perform well in consistently moist soils, especially during their active growth and blooming seasons in spring and summertime. As a general rule of thumb, water whenever the top inch or two of soil feels dry to the touch.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants. Prune the plant for size and shape immediately after flowering ends to avoid cutting off the buds for next year's blooms; Mahonia blooms on old wood. Mahonia shrubs are long-lived perennials, and typically survive in the landscape for between 15 and 20 years or more with proper care. These shrubs will spread via underground suckers that can be removed from the parent plant, providing new shrubs for the landscape indefinitely.

Propagation

Mahonia shrubs can be propagated either by using cuttings or from seed. The more simple, straightforward method is the cutting method; the seeds take a while to prep before they are ready to sow. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Mahonia by Cutting
  1. Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. In spring or early summertime, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more softwood 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
  3. Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
  4. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Mahonia by Seed
  1. Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a bowl filled with water, a sealable plastic bag or container, peat moss, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
  2. Harvest your seeds in late summer to early fall. The seeds on Mahonia shrubs are contained inside the fruits, so just as they  become ripe, pick them off of the plant and bring them into your work area.
  3. Remove the seeds from the fruits by either crushing them or cutting them open, and rinse them to get off any flesh. Then, soak the seeds in water for 48 hours. After this treatment, remove the seeds from the water and place them in a sealable bag filled with moistened peat moss. The seeds should be kept in this bag for 2 months at a temperature of about 70 degrees Fahrenheit, and then transferred in the same bag to an area where they are kept at about 37 degrees Fahrenheit for an additional 5 months.
  4. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 3-4 weeks from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
  5. Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 65 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.
Mahonia berries can contain anywhere between 2 and 10 seeds each.
Mahonia seeds are small, hard, dark reddish to brown, and teardrop-shaped.

Problems and Pests

Certain species of Mahonia are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Generally pest-resistant, but foliage can sometimes be used by caterpillars as a food source. You should also keep an eye out for the following common garden pests:
  • Aphids
  • Scale Insects
For more information on these issues, including how to solve and prevent them, see the links below:
​

Gallery

Mahonia flowers in late winter to early springtime. The blooms smell like citrus.
These shrubs can grow to have a bit of an awkward habit, so make sure to train them how you want them when they are young.
These shrubs are wonderful screens for walls and other outdoor eyesores.
Some species listed above are great understory shrubs that prefer to be planted in full to partial shade.
Even when not in bloom, these evergreen shrubs are beautiful additions to any garden.
A photo I snapped of a Mahonia outside of a cafe in Fremont, CA (December 29th, Zone 17). It was growing in a parking lot planting strip, and not doing so hot, but still produced flowers.

Videos

All about the different varieties of Mahonia.
How to grow an Oregon Grape shrub.
Learn about these versatile garden shrubs.
How to prune Mahonia shrubs.

Resources

Native Plant Network - Mahonia Propagation Protocol
Planning Your Shade Garden With Mahonia
How to Grow and Care for Mahonia
Wikipedia: Mahonia
The New Sunset Western Garden Book: The Ultimate Gardening Guide (2012) - Pages 431 - 432, Mahonia