Ninebark

By Kim Willis These articles are copyrighted and may not be copied or used without the permission of the author.

Ninebark, Physocarpus opulifolius, is everything most gardeners could want in a shrub.  It’s native to central and eastern North America, has beautiful fragrant flowers in spring that bees and butterflies adore, seeds that birds like, good fall color and interesting exfoliating bark for winter interest.  Many cultivated varieties also have colorful summer foliage. 

 Ninebark is a shrub, the native species is about 10 feet high by 10 feet wide but more compact and shorter varieties have been developed so almost any gardener can fit one in somewhere and they are well worth including in the garden.  Native wild type ninebark is hardy from zones 2-8 and while they like full sun in the north will grow in partial shade further south.  Ninebark is drought tolerant once established and will grow in almost any kind of well-drained soil.

Ninebark is tough and fast growing, blooming when 2-3 years old.  It has few pests or disease problems; powdery mildew sometimes hits the wild form and some cultivars but doesn’t seriously harm the plant.  Many cultivated varieties have good powdery mildew resistance.  Some nurseries and garden writers list ninebark as deer proof but in my garden deer did prune the plants somewhat for me, although they only ate the branch tips.  Ninebark will also grow close to black walnut trees.

Ninebark generally forms a multi-stemmed, rounded, somewhat arching or weeping shrub.  Older stems will have bark that peels in strips, revealing layers of different colored bark, which is where the name ninebark is supposed to come from.  The bark is visible in winter.  Ninebark sometimes suckers, but is not considered to be an aggressive spreader. 

Ninebark has oval, 3-5 lobed leaves, which are thick and somewhat rough, with toothed edges.  Many cultivated varieties have finer foliage.  The species has plain green leaves that turn yellow in fall.  But there are many cultivated varieties with maroon, purple, or golden foliage that is pretty in summer and has lovely fall color.

The flowers of ninebark are beautiful as well as fragrant.  Some writers describe them as spirea- like, but I see nothing spirea about them, except that they bloom close to the same time.  The shrub is covered in late spring- early summer with rounded clusters of small five petaled flowers.  The clusters range from golf ball to tennis ball size.

In the species and golden leaved varieties the buds are light pink and the open flowers white.  In dark leaved varieties buds are darker pink and the open flowers are white flushed with pink.  In newly opened flowers the cluster of stamens in the center have red tips, which darken as they age.  Bees and butterflies flock to ninebark in bloom, attracted by the light sweet scent and abundant nectar the plant produces.  If you pull the petals from a flower you’ll see drops of nectar in the cup of the remaining sepals.

The flowers turn into reddish inflated seed pods in dangling clusters.  Songbirds enjoy eating the seeds and the capsules themselves provide some winter interest until the birds eat them.

Varieties of ninebark

‘Dart's Golden’ ninebark is a variety with golden yellow spring foliage fading to lime or chartreuse in summer, which becomes golden tinged with orange in the fall.  It’s a bit more compact than the species at 6 feet tall and wide. It’s hardy in zones 3-8.

'Nugget' Ninebark  is a compact variety, growing 5 to 6 feet high and wide. The leaves are a bit more finely-textured than the species, golden yellow in the spring maturing to lime green foliage. Zones 3-8

 'Amber Jubilee’ or 'Jefam' Ninebark is also a compact variety, 5 to 6 feet high and 3 to 4 feet wide.  Spring growth is yellow orange, summer color lime green and fall color is purple.  Zones 3-7.

‘Center Glow’ ninebark has purple foliage with a gold center in spring, fall color is purple red.   It’s a full sized ninebark- 8 or more feet high and wide.  Hardy in zones 3-7.

‘Coppertina’ ninebark is a full sized ninebark with coppery purple spring foliage, purple summer foliage and red-purple fall foliage.  Hardy in zones 3-7.

‘Diabolo’ or ‘Monlo’ ninebark is a large ninebark with deep burgundy purple foliage all year.  It has some mildew resistance.  Zones 3-8.

‘Little Devil’ or'Donna May' ninebark is a dwarf selection of Diablo, with fine textured very deep purple foliage all year.  It grows 4 feet tall and wide and is mildew resistant.  Zones 3-7.

‘Summer Wine’ or  'SWPOTWG' ninebark is compact , growing about 5 feet tall and wide.  It has good purple foliage all year, pink tinged flowers and is quite resistant to mildew.  Zones 3-7.

 Tiny Wine® is one of the newer and smaller varieties at only 3-4 feet high and wide.   It has fine-textured, deep purple leaves  and is mildew resistant, and would be excellent for smaller gardens.  Zones 3-7.

 Planting and care of ninebark

Ninebark is usually purchased as a plant, especially if you want a cultivated variety.  These are generally started from cuttings.  Seed from ninebark is relatively easy to grow but you probably won’t get seed grown plants that look like their parent unless you are using the seed from wildtype plants.  Plant seeds in pots in the fall after they ripen and leave the pots outside through the winter for best germination.  Ninebark suckers can be dug up and transplanted.

In planting zones 2-6 I would try to place your ninebark in full sun. In higher zones they will do well in partial shade.   They need well drained soil but aren’t fussy about soil type. Don’t amend the soil in the hole when planting.  Back fill with the soil you removed, no matter how poor you think that soil is.  One application of a general purpose fertilizer for shrubs should be given at planting and then once a year in early spring.  Don’t over fertilize.

Keep the ninebark watered during the first year as it establishes itself. After that they rarely need supplemental water unless it’s very dry for long periods.  Ninebark doesn’t do well in wet soil areas.

Ninebark can be pruned to shape it and control height but it must be pruned immediately after flowering, no later than July 1, if you want flowers the next spring.  If you have a badly overgrown and wild looking ninebark you can prune it back to a foot from the ground but expect it to take two years before it blooms again.

Powdery mildew can be avoided by placing plants where they get good air flow and planting resistant varieties. 

Medicinal and other uses of ninebark

The inner bark of ninebark is powdered and used as a laxative tea.  Indigenous people used a cooled tea as a vaginal douche, said to cure infertility, delayed menstruation (which suggests it may be an abortifacient) and infections.  All plant parts are toxic and only experienced herbal practitioners should use it.  Ninebark bark was mixed with cedar bark and used as a brown dye.

 Ninebark is a great shrub for a blooming and colorful hedge.  You could alternate plants with different color foliage.  Smaller cultivars look good in butterfly and bee beds or mixed perennial plantings.  One of the nicely colored cultivars could be used as a specimen plant or garden focal point.