Common ninebark (Physocarpus opulifolius) is a versatile flowering shrub native to North America, which gets its name from attractive bark that peels away and is said to have nine layers. The species is available in many cultivars and can handle many types of growing conditions. It is widely used for landscaping in all but the warmest climate zones. The plant is sometimes known as common ninebark or eastern ninebark.
Ninebark is a large shrub with dark green or reddish leaves that form an arching, cascading habit. The leaves are 3 to 4 inches long, with a lobed structure that resembles that of Viburnum. Ninebark flowers in late spring with clusters of white or pink blooms, and it has red fruit that provides fall interest as well as food for birds. This shrub is related to spirea and has similar clusters (umbels) of flowers that develop into red inflated fruit (follicles) in the fall.
Ninebark cultivars are available in many sizes, with a mature height ranging from 5 to 10 feet, with a spread of 6 to 8 feet. There are also dwarf varieties available that reach only 3 to 4 feet in height and spread.
Physocarpus opulifolius is a member of the Rosaceae family, which also includes roses, cotoneasters, and the Prunus group of fruit trees. The shrub is found naturally in abundance in eastern North America on hillsides and stream banks, but ranges across the eastern U.S. into the Dakotas on the west and southward to northern Florida. Northward, it extends well into Canada. It is hardy to USDA hardiness zone 2, and grows well down through zone 7. It may struggle in the heat of zones 8 and 9. One variety is also found in the Rocky Mountains and westward to Oregon and Washington.
Ninebark is a very easy to grow, hardy plant with few pest or disease issues. Its easy-going nature combined with its attractive growth habit and flowers make it a favorite for landscaping, where it is used for specimen planting, for foundation plantings, for hedges, or to prevent erosion on slopes. Many cultivars are available. Once established, ninebark is a very good, drought-resistant shrub for dry areas.
Ninebark should be given enough space so that its arching branch pattern can be fully appreciated. When used in a mixed shrub border, it works well with lilac and spirea.
Growing Ninebark Shrubs
Plant in a location that receives full sun to part shade, but be aware that it will flower best in full sun. Ninebark will grow in both dry and wet locations, and it can tolerate either alkaline or acidic soil. It really is quite hardy and will be a champ in rough spots.
In spring, mulch the shrubs with a layer of bark mulch or wood chips to keep the soil moist and to hold down weeds. Spring is also the best time to lightly fertilize with compost and organic plant food.
Pruning is rarely needed, but when necessary, prune it after flowering or no later than mid-August. Occasional heavy rejuvenation pruning may sometimes be necessary to renew the plant and encourage better leaves and flowers.
Varieties with purple leaves:
- 'Center Glow'—yellow center surrounded by purple
- 'Mindina' (sold under the name Coppertina™)
- 'Monlo' (better known as Diablo®)
- 'Seward' (Summerwine™)
Varieties with yellow leaves:
- 'Dart's Gold'
This shrub is remarkably free of pest problems. Fireblight and leaf spots may occur, and powdery mildew can strike if the leaves stay wet. Deer do like to nibble on ninebark. If branches die back, the shrub will spring to life after heavy pruning, even down to ground level.