Physocarpus, commonly called ninebark, is a genus of in the family Rosaceae, native to North America (most species) and northeastern Asia (one species).
The genus name Physocarpus comes from the Greek for "bladder fruit", referring to the inflated fruits of some species.
Description
Physocarpus are
deciduous shrubs with peeling bark
[ Physocarpus opulifolius 'Diabolo'. Missouri Botanical Garden.] and alternately arranged leaves. The leaves are palmate with 3 to 7 lobes and often toothed edges. The
inflorescence is a cluster of bell-shaped flowers with 5 rounded white or pink petals and many
. The fruit is a flat or inflated dehiscent follicle.
[ Physocarpus. The Jepson eFlora 2013.][ Physocarpus. Flora of China.]
Physocarpus opulifolius is cultivated as an ornamental plant. Several cultivars have been bred, particularly for foliage of varying colors, including 'Dart's Gold' and 'Luteus', which have yellowish leaves, and 'Monlo' and 'Seward', which have reddish purple foliage.[ Common Ninebark, Physocarpus opulifolius. University of Illinois Extension.]
Taxonomy
Species
There are six
[Oh, S. H. and D. Potter. (2005). Molecular phylogenetic systematics and biogeography of tribe Neillieae (Rosaceae) using DNA sequences of cpDNA, rDNA, and LEAFY. American Journal of Botany 92(1), 179–92.][Oh, S. H., et al. (2010). Phylogenetic relationship of Physocarpus insularis (Rosaceae) endemic on Ulleung Island: implications for conservation biology. Journal of Plant Biology 53(1), 94–105.] to 20
species in the genus. They include:
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Physocarpus alternans – dwarf ninebark (western North America)
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Physocarpus amurensis – Asian ninebark (Asia)
[ P. amurensis Flora of China. Retrieved 22 January 2012.]
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Physocarpus australis
[ P. australis International Organization for Plant Information (IOPI). Retrieved 22 January 2012.]
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Physocarpus bracteatus – (Colorado)
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Physocarpus capitatus – Pacific ninebark (western North America)
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Physocarpus glabratus – (Colorado)
[ P. glabratus Tropicos.org. Missouri Botanical Garden. Retrieved 22 January 2012.]
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Physocarpus malvaceus – mallow ninebark (western North America)
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Physocarpus monogynus – mountain ninebark (North America)
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Physocarpus opulifolius – common ninebark (eastern North America)
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Physocarpus pauciflorus
[ P. pauciflorus International Organization for Plant Information (IOPI). Retrieved 22 January 2012.]
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Physocarpus ribesifolia
[ P. ribesifolia Tropicos.org. Missouri Botanical Garden. 22 January 2012] – (Asia)
Synonyms
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Physocarpus hanceana = Neillia hanceana
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Physocarpus intermedius = Physocarpus opulifolius var. intermedius
[ P. intermedius Tropicos.org. Missouri Botanical Garden. Retrieved 22 January 2012.]
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Physocarpus torreyi = Physocarpus monogynus
[ P. torreyi Integrated Taxonomic Information System (ITIS). Retrieved 22 January 2012.]
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Physocarpus stellatus = Physocarpus opulifolius
Cultivation
Propagation is by seeds sown as soon as ripe or they can be stored dry in airtight containers in a cool place for up to a year and then sown. Plants can be divided in the early spring, with a sharp spade or even an axe, chopping right through the middle. Softwood and hardwood cuttings are easy to root.
Garden writers describe few if any problems, but it is not unheard for armies of aphids to attack some varieties. Some seaside specimens exhibit powdery mildew in summer.
