Ninebark is a native perennial shrub that likes to be near moisture, growing to 10 feet tall on multiple stems that are frequently branched. The branches are long, re-curved, and the old bark on branches will peel in layers or strips, hence the common name "Ninebark". Young stems are green, older stems turn a darker reddish-brown.

Leaves are alternate and larger lower leaves will have 3 to 5 pointed lobes (resembling maple leaves). The overall shape is ovate to oval with coarse teeth or dentations on the margins of the lobes. Upper leaves are smaller with less pronounced lobes. The upper surface is smooth while the lower surface has some sparse whitish hair on the veins. Leaves are stalked and at the base of the stalk is a pair of very small pointed stipules. Fall color can be yellow to a purplish red.

The inflorescence is an upright rounded cluster that looks like an umbel but is technically an open hemispheric raceme of showy 1/2 inch wide white stalked flowers.

The flowers are 5-parted with a cup-shaped hypanthium that is a yellow-orange color with 5 light green triangular calyx lobes. When the flower opens, these reflex and turn whitish. The corolla has 5 white petals with rounded tips, numerous stamens with reddish anthers, and 5 styles from the ovary.

Fruit: The fruit is an inflated seed capsule (a follicle) for each flower, borne in the upright cluster, turning to a reddish brown in the fall and by that time the cluster is usually drooping. Each capsule may have from 3 to 5 chambers and when mature, the capsule splits along two sides and releases a shiny reddish tear-drop shaped seed that has a beak at one end.

Habitat: While commonly found in moist areas the shrub is adaptable to other moisture conditions with full sun to partial shade. It can be propagated from seeds or cuttings; seeds require no pretreatment to germinate; the plant can be transplanted when young. When well established however, it is well grounded and would require heavy equipment to fully remove.

Names: The genus name Physocarpus, is from two Greek words, physa, meaning "a bladder" and karpos, meaning 'fruit', in total - 'bladdery fruit' referring to the way the seed is held in a bladder like cover. The species name opulifolius, is a bit obscure and refers to leaves like the "opulus". Opulus, is taken directly from the Greek where it referred to a type of maple and was applied here due to the maple-like leaf shape. The author name for the plant classification, ‘Maxim.’ is for Karl Maximovich, (1827-1891) Russian botanist who extensively studied and wrote about the flora of the far east. His work updated that of '(L.)', which refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.

Comparisons: While somewhat resembling the Spireas this shrub is distinguished by the shedding bark and the clusters of inflated fruits. See notes below on varieties.