Mallow Ninebark

**Mallow ninebark** (*Physocarpus malvaceus*) is a deciduous shrub native to the Intermountain West. Its palmately lobed leaves, clusters of small flowers and shredding older bark give it interest beyond bloom season. ## Seasonal character and placement The U.S. Forest Service describes the accepted species and its regional range in its [mallow ninebark review](https://research.fs.usda.gov/feis/species-reviews/phymal). It reports mature heights of about 2–7 feet, flowering from May through July, and brownish-red foliage by early autumn. The shrub occurs on hillsides, canyons, grasslands and woodland sites from British Columbia and Alberta south through the western United States. Use it in a naturalistic shrub planting or at a woodland edge where a spreading native shrub fits. ## Growing conditions Recorded sites include moist slopes and stream edges as well as mesic ponderosa pine and Douglas-fir communities. Soils range from sandy loams to silty clay loams. These varied settings support a flexible site choice; favor well-drained soil and observe local moisture rather than applying one fixed watering schedule. ## Maintenance This species has a horizontal rhizome system and may increase its cover through vegetative growth. Allow room for that spreading habit, and check the planting edge periodically where it must stay within a defined bed. The cited profile documents wild-site ecology, not a universal pruning calendar, so maintenance should follow the shrub’s growth in its particular garden setting.