Ninebark, Common - Physocarpus opulifolius
Physocarpus opulifolius, otherwise known as Common Ninebark, is a perennial deciduous shrub native to Michigan and the UP. This 6 to 9 foot shrub has nicely textured, bright green leaves and lovely pink buds which open to white flowers in June. The following seed capsules are dark pink to almost red. Because of the long bloom time, the plant may have white flowers and red seed heads at the same time, making for a striking display. But the unique feature of this shrub is its naturally textured bark. The bark turns into fluttery strips that curl like the number 9 as the branch ages, giving the plant its name and providing a lot of garden texture and winter interest.
If there is no competition, this plant will get nearly as wide as it is tall. Birds appreciate the cover provided by the arching branches as they forage for insects among the leaves or leaf litter, or while eating seeds in the winter. The dense branches make this a good choice for a privacy planting, but mature plants can be cut to the ground to control their size (although I have literally had chickadees cuss me out for trimming their favorite shrub. Trim only if absolutely necessary.)
As for insects, according to illinoiswildflowers.com, the profuse blooms of this shrub in late spring or early summer attract bees, wasps, flies, and butterflies. Common Ninebark (not ninebark cultivars) also hosts a variety of interesting moths, including Schizura unicornis, the Unicorn Caterpillar. In turn, some of the caterpillars feed the young of birds like chickadees, making this an excellent plant for birds.
Ninebark is very versatile, handling sun or part shade, sand or clay, compacted or loose soils, dry or wet, drought or flood. In the UP, it is most common in rocky areas or near rivers, or even on sandy shores. It can be used to control erosion on slopes or banks, but it is usually grown as an ornamental. The spring flowers are followed by pink seed heads that turn from pink to yellow to tan and persist through winter, upping the habitat and winter interest value of this shrub. For best seed production, plant three or more to improve pollination rates.
Cultivars abound, but alterations to leaf color or other aspects can affect the ability of beneficial insects and birds to use this shrub as part of their life cycle. We whole-heartedly recommend using the straight native species "Common Ninebark, Physocarpus opulifolius" with no fancy name added on indicating cultivars.
We are now growing our Common Ninebark from UP-sourced seed. Quart pots contain first or second year plants, typically 4" to 8" tall. The "5 Quarts" option is 5 separate quart pots, which is an excellent bargain. Larger stock is sold in gallon pots.
For more information:
https://plants.usda.gov/DocumentLibrary/plantguide/pdf/pg_phopo.pdf
https://minnesotawildflowers.info/shrub/ninebark
http://illinoiswildflowers.info/trees/plants/ninebark.htm