Mountain Ninebark 'Grey Rock' (Physocarpus monogynus) was a naturally occuring cultivar found in the Cache la Poudre Canyon in Colorado. This attractive native shrub maintains a 3-4' mound and features attractive green foliage, corymb-shaped groups of white or light pink flowers in the early summer that give way to red seedheads, red and orange leaf color in the fall, and bark that peels in papery strips to reveal chocolate-covered bark beneath. Mountain Ninebark is excellent for traditional beds and borders, dry shade or woodland gardens, or for use as a low hedge. Ninebarks are usually very tolerant of urban pollution.
Mountain Ninebark 'Grey Rock'
Native to Cache County: No
Irrigation Requirement: Low (1/2" every 10-14 days) or Moderate (1/2" every 7-10 days)
Mature Size: 3 - 4' tall and wide
Spacing: 3 - 5' apart
Bloom Colors: White or Pink
Bloom Season: June
Hardiness Zone: 3 - 7
Light Requirement: Full Sun or Partial Shade
Deer Resistant: Yes
Salt Tolerant: No
Soils: Tolerant of many soil types as long as they are well-drained, including sand, loam, or non-heavy clay.
Plants in the Physocarpus genus are host plants for up to 13 local polliantors in the northern Utah area. Ninebark is also an excellent habitat plant when massed under trees, provides pollen and nectar for local pollinators, and the seeds are eaten by many types of birds.