[Ninebarks: The Genus Physocarpus East
of the Cascade Mts. of Oregon and Washington]
Mallow Ninebark, Few-flowered Ninebark
Physocarpus malvaceus
Synonyms: Neillia malvacea, Neillia monogyna, Neillia monogyna var. malvacea, Neillia torreyi, Opulaster cordatus, Opulaster pauciflorus, Opulaster pubescens, Physocarpus pauciflorus, Spiraea opulifolia var. pauciflora, Spiraea pauciflora
The photo above shows a close-up of the inflorescence of mallow ninebark as seen several hundred meters below the summit of Chewelah Peak in the Colville N.F.........June 23, 2006. Mallow ninebark differs from the similar Pacific ninebark in generally having 2 pistils while the latter has 3-5 pistils. The flowers seen above have 2 pistils.
Photo
at right of the upper surface of a leaf of mallow ninebark from Squaw Creek Viewpoint
off of Interstate 84, east of Pendleton, OR.......July 6, 1999.
Characteristics:
Mallow ninebark is an attractive shrub with several to many
spreading to erect branches from 0.5-2 meters high. The leaves alternate along
the branches and are simple with ternate venation (3 main veins) with the blades
ovate to heart-shaped and with 3-5 lobes which are incised less than half the
length. The lobes are rounded to acute and doubly toothed. The leaves are 4-8
cm long and almost as wide. The upper surface is dark green and smooth while
the lower surface is lighter and abundantly haired.
The flowers are in corymbs or small hemispheric clusters of
many white flowers. Each of the 5 petals is suborbicular and up to 4 mm long.
The flowers have about 30 stamens which equal or slightly exceed the length
of the petals, and usually 1-2 pistils, although 4-5 pistils are possible.
In general, this species is similar in appearance to Physocarpus
capitatus, but mallow ninebark generally has smaller leaves and a slightly
smaller inflorescence, and it is shorter in stature.
Importance:
Mallow ninebark is browsed occasionally by wildlife. It grows
aggressively following a fire. It would also make an attractive shrub for the
woodland or shrub-steppe garden on the east side of the Cascades.
Habitat:
Mallow ninebark may be found beneath ponderosa pin and Douglas-fir
on canyon slopes or valley bottoms. It may also be found on nonforested scrubland
sites.
Range:
Mallow ninebark may be found from southern British Columbia
south along the eastern edge of the Cascades to central and eastern Oregon.
It is found eastward to the Rocky Mts. of Southwestern Alberta, Montana, Wyoming,
and Utah.
This photo shows a good view down onto the flower, showing the numerous stamens and the two-carpe pistil with 2 styles of mallow ninebark. Photographed off Interstate 84 east of Pendleton, OR at the Squaw Creek Viewpoint in the Umatilla National Forest..........June 25, 2008.
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Close-ups of mallow ninebark as seen along the Umatilla Rim Trail in a clearcut about one-third mile north of the junction with the Lake Creek Trail, Umatilla National Forest.........June 30, 2012.
The photos above show 3 close-ups of the flowers of mallow ninebark as seen about 10 miles up Hat Pt. Road in Hells Canyon National Recreation Area..........May 28, 2007. Note that one hair covered pistil is present at the center of the flower.
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The photo at left shows several rounded inflorescences and leaves of mallow ninebark as seen several hundred meters below the summit of Chewelah Peak in the Colville N.F........June 23, 2006. The photo at right shows mallow ninebark along the forested trail along the northern portion of the loop trail system originating from the Painted Rocks, Little Spokane River Natural Area.........May 9, 2016.
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Mallow ninebark as seen along trails in Field Springs State Park, Asotin County, Washington............June 11, 2013.
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Mallow ninebark blooming at left along the old road in Sourdough Gulch, Asotin Wildlife Area, Asotin County, WA........June 3, 2017. Mallow ninebark blooming along Forest Road #3965 about one mile or so west of the Hells Canyon Overlook, Hells Canyon National Recreation Area........June 11, 2018.
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Mallow ninebark blooming on wooded ridges on the eastern outskirts of Woods Bay, Montana......May 27, 2023.
Paul Slichter
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