Garden Planner Growing Information for Mahonia

Mahonia

Crop Rotation Group

Miscellaneous

Mahonia, also known as Grape Holly, Oregon Grape, Holly-leafed Barberry

Soil

Moist, well-drained soil enriched with plenty of compost or other organic matter.

Position

Partial shade.

Frost tolerant

Cold tolerance varies with cultivar, with many mahonias hardy to -5°F (-21°C).

Feeding

Topdress the root zone with a balanced organic fertilizer in spring, and keep plants mulched year-round to protect the plants’ shallow roots.

Companions

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Spacing

Single Plants: 3' 3" (1.00m) each way (minimum)
Rows: 3' 3" (1.00m) with 3' 3" (1.00m) row gap (minimum)

Sow and Plant

Set out purchased plants from spring through early summer, setting them slightly high in the planting hole so the top of the root ball is barely covered with soil. Water regularly, and cover the root zone with an organic mulch to keep the soil moist at all times. Once established, mahonia is reasonably drought tolerant. Spacing varies with the type grown, because mahonias vary from 3 feet 3 inches (1m), the mature spread of creeping mahonia, to 6 feet 6 inches (2m) for upright cultivars. Check plant tags for a plant’s mature height and width. For containers, use one dwarf plant per 14-inch (35 cm) pot.
Our Garden Planning Tool can produce a personalized calendar of when to sow, plant and harvest for your area.

Notes

Mahonias are valued for their large, holly-like evergreen leaves, fragrant yellow flowers that appear in winter, and loose clusters of dark purple berries. The berries are relished by birds, but too tart for most human palates. Several garden-worthy species are native to North America. Mahonias do not like to be moved and often take a year or more to commence rapid growth. Once established, they will flourish for many years. Rather than having spiny leaves, ‘Soft Caress’ mahonia has finely cut palm-like foliage. It is often used as a texture plant in containers. Once-popular leatherleaf mahonia (M. bealei) is listed as an invasive plant by many states in the Southeastern US. Mahonias need little pruning. When flowering ends in spring, trim the plants as needed to remove damaged branches and to help define the natural shape of the shrub.

Harvesting

Depending on climate, mahonias may bloom in winter or spring, but always in chilly weather. On warm days, bees and other insects may be seen visiting the lightly fragrant blossoms. For many gardeners, this is the main reward for growing a mahonia.

Troubleshooting

Winter leaf scorch can occur when mahonias are grown in sites exposed to cold winter winds. In alkaline soils, mahonias may have trouble taking up nutrients. Mahonias are seldom browsed by deer.