There are many Mahonias used in gardens for shady areas. They are evergreen and usually have spiny leaves and make good barrier plants. They have yellow flowers and generally bloom in the winter or spring. 
Chinese Hollygrape (Mahonia lomariifolia). Very upright and sculptural plant. Blooms December – February.
Oregon Grape (Mahonia aquifolium)
State flower of Oregon
California Holly Grape (Mahonia pinnata)
These spines are very sharp; you must wear gloves to prune it.
Japanese Mahonia (Mahonia japonica)
Mahonia media ‘Charity’
Mahonia media ‘Morning Sun’
Mahonia bealei
Mahonia repens Notice on the lower photo how the rhizomes creep into other areas and can be invasive. But it is a good ground cover for dry shade. It survives with no water all summer at Dawn Gardens.
Mahonia haematocarpa
Mahonia nervosa
Mahonia ‘Soft Caress’
One of the new Mahonia cultivars that have no spines
Mahonia ‘Marvel’
