Culture
Easily grown in average, slightly acidic, dry to medium moisture, well-drained soil in full sun to part shade. Best in full sun in the northern part or its growing range, but appreciates some afternoon shade in the St. Louis area. Tolerates a wide range of soil conditions. Prune as needed immediately after bloom and no later than mid-August. Plants may be cut close to the ground in early spring to rejuvenate. Plants often struggle in the hot and humid summer climates of the deep South in USDA Zones 8-9.
Noteworthy Characteristics
Physocarpus opulifolius, commonly called ninebark, is an upright, spreading, somewhat coarse, deciduous, Missouri-native shrub which is closely related to the genus Spiraea. In Missouri, it typically occurs along streams, rocky banks, gravel bars and in moist thickets, especially in counties south of the Missouri River (Steyermark). Grows 5-9’ tall (less frequently to 10’). Noted for its exfoliating bark (on mature branches) which peels in strips to reveal several layers of reddish to light brown inner bark (hence the common name of ninebark). Bark provides winter interest, but is usually hidden by the foliage during the growing season. Features small pink or white, five-petaled flowers appearing in dense, flat, rounded, 1-2” diameter, spirea-like clusters (corymbs) in late spring. Flowers give way to drooping clusters of reddish fruit (inflated seed capsules). Ovate to rounded, usually 3-5 lobed leaves (to 4” long) are dull green in summer changing to an undistinguished yellow in fall.
Genus name comes from the Greek physa meaning a bladder and karpos meaning fruit, referring to the inflated dry fruits of the plant.
Specific epithet refers to the leaves that resemble those of Viburnum opulus.
Common name of ninebark is in reference to its ornamental attractive exfoliating bark.
'Diabolo' is a purple-leaved ninebark cultivar. Like the species, it is an upright, spreading, somewhat coarse, deciduous shrub which is closely related to genus Spiraea. It typically grows 4-8' (less frequently to 10') tall. Small pinkish-white, five-petaled flowers in dense, flat, rounded, 1-2" diameter, spirea-like clusters (corymbs) appear in late spring. Flowers give way to drooping clusters of reddish fruit (inflated seed capsules). Ovate to rounded, usually 3-5 lobed leaves (to 4" long) are dark purple. Purple foliage tends to green up in hot summer climates as the summer progresses. The species is native to Missouri. Ninebark is named for its exfoliating bark (on mature branches) which peels in strips to reveal several layers of reddish to light brown inner bark. Bark provides winter interest but is usually hidden by the foliage during the growing season.
Problems
Fireblight, powdery mildew, and leaf spots may occur.
Uses
Mass in shrub borders. Effective as hedge, screen or for erosion control on banks. Native plant garden. Able to grow in harsh conditions.
Specimen.