Physocarpus opulifolius
A versatile shrub, eastern ninebark (Physocarpus opulifolius) provides year-round interest. In late spring, round clusters of flowers dot the shrub in white and attract pollinators like bees and butterflies. Dense branching provides shelter for nesting birds.
As the flowers fade, reddish seed capsules form, adding a pop of colour that lasts all summer long. The flowers and seed clusters can be so abundant, longer branches arch downwards from the weight, creating a waterfall-like effect. In the summer, watch for the unique caterpillars of cecropia, blinded sphinx and unicorn caterpillar moths, who use ninebark as a host plant.
Once the leaves fall, the unique peeling bark of eastern ninebark becomes visible. Seed clusters turn brown and often cling to the branches. During a snowfall, these clusters catch the snow and look as if they’re wearing little snow hats.
Growing Conditions and Maintenance
Eastern ninebark does well in full sun to part shade and moist loam to clay soils, growing 1.5 to 2.5 metres tall and up to 3 metres wide (be sure to give it some space to fill in when planting). Ninebark also tolerates drier conditions, as well as salt and compaction in urban areas.
After it flowers, prune ninebark to maintain its shape, keeping in mind you’ll have less showy seed clusters in the fall. If heavier pruning is needed to manage size, wait until late winter to prune/trim.
Consider grouping with other trees and shrubs to create a privacy hedge, including species such as common elderberry, grey dogwood, purple-flowering raspberry, downy serviceberry and alternate-leaved dogwood.