Common Ninebark (Physocarpus opulifolius) is an underrated native shrub with four-season interest. This native species is a graceful arching shrub with clusters of creamy white spring flowers followed by showy seed capsules and yellow-orange fall color. Winter interest is provided by the exfoliating bark that gives the plant its common name, derived from the appearance of many layers or strips of bark on the stems.
Native songbirds utilize this peeling bark as nesting material and take shelter in the dense branching habit for nesting sites. Common Ninebark is found in our Wisconsin woodlands as an understory shrub as well as in open areas and is adaptable to growing in light conditions ranging from partial shade to full sun. It will reach a mature height of 6’-10’, with an equal spread.
Caring For & Maintaining Your Ninebark
Ninebark is an easy-care shrub. It is very cold hardy and well adapted to growing in our alkaline soils. It will require regular, thorough, watering for the first season when transplanted, but after that will be fairly drought tolerant.
An annual spring application of slow-release, organic fertilizer, combined with deep watering at the base of the plant during periods of drought, will keep your Ninebark vigorous. Plants in good health are best able to resist damage by disease and insect pests. Stressed Ninebark plants can become susceptible to powdery mildew, especially during our hot, humid Wisconsin summer months.
Powdery mildew is a fungal disease that causes white powdery growth on foliage. While it is primarily an aesthetic issue and ordinarily will not harm the plant, it can be unsightly. Since fungal disease treatment consists of prevention, fungicide spray should be applied as soon as the first signs of mildew are seen. There are several fungicides, both organic and conventional, that can prevent powdery mildew. Read more about Insect, Disease & Weed Control.
How Do You Prune Ninebark?
In youth, Ninebark grows in a somewhat dense, compact habit. As it matures it takes on a looser, arching, fountain-like growth form. Minimal pruning is necessary but if it is desired I recommend pruning to maintain the plant’s distinctive form. Achieve this by selectively removing only branches that are older, damaged, crowded, or crossed. This pruning method will also increase air circulation, which will aid in avoiding powdery mildew.
Ninebark in a Nutshell
- Mature height: 3′-8’, depending on cultivar
- Mature spread: 3′-8’, depending on cultivar
- Light requirement: Full sun to light shade
- Growth form: Dense, upright, spreading habit. Individual branches arch to the ground in a fountain-like fashion.
- Flowers: Abundant tubular flowers in late spring/early summer. Colors include shades of pink, white, and true red.
- USDA Hardiness Zone: Zone 4
- Especially valuable for:
- Cold hardiness
- Foliage color (cultivars)
- Interesting fruit
- Shelter and nesting sites for native songbirds
- Moderate deer resistance
- Common Ninebark is a good choice for naturalized shrub borders
- Cultivars selected for the compact habit are good for foundation plantings
- Cultivars selected for leaf color can be used as specimens or combined with evergreens or other deciduous shrubs as a color contrast in shrub borders.
Ninebark Cultivars
There has been much work done among plant breeders to select for new Ninebarks with such garden-worthy qualities as compact size and interesting foliage color. A few of the varieties we grow include:
by Zannah Crowe
