'Blue River II' Hibiscus (Hibiscus x moscheutos) Has Pure White Flowers

Summary: 'Blue River II' hibiscus (Hibiscus x moscheutos), a cultivar of crimsoneyed rosemallow and halberdleaf rosemallow, has pure white flowers.

‘Blue River II’ hibiscus in the company of Cleome ‘Sparkler White,’ Evening Island, Chicago Botanic Garden, July 25, 2016: K M (cultivar413), CC BY 2.0, via Flickr

'Blue River II' hibiscus (Hibiscus x moscheutos), a cross of New World native perennials crimsoneyed rosemallow (Hibiscus moscheutos) and halberdleaf rosemallow (Hibiscus militaris), frames large, pure white flowers with blue-tinged, deep green foliage.

'Blue River II' hibiscus lays claim to stellar parentage as a cross of two cold-hardy, large-flowered, North American native hibiscus species. Both crimsoneyed rosemallow and halberdleaf rosemallow are popular in hibiscus hybridization programs.

Crimsoneyed rosemallow and halberdleaf rosemallow both proliferate natively across the central and eastern United States. Crimsoneyed rosemallow also claims native status in two southwestern states, New Mexico and Utah. For both species, their only nativity in Canada occurs in the east central province of Ontario.

Hibiscus ‘Blue River II’ puts forth stems that may attain sturdy heights of 4 to 5 feet (1.21 to 1.52 meters). A pleasing, shrubby spread tends to maximize at 2.5 to 3 feet (0.76 to 0.91 meters).

Alternate arrangements along stems characterize leaf growth. Large leaves are colored deep green and sometimes have blue tinges.

'Blue River II' hibiscus features a lengthy blooming period that stretches across two seasons, from midsummer to mid-autumn. Flowers open in July. Successive bloomings occur through September and may last until the first frost. Each flower opens ephemerally, for one full day.

Hibiscus 'Blue River II' has large flowers that are known as dinner-plate-sized flowers. Floral diameters may reach 10 inches (25.4 centimeters).

Five overlapping petals are pure white. The absence of a contrasting eye, at the base of the petals, heightens the flower’s showy whiteness and spotlights the prominent staminal column that is a noticeable feature of hibiscus flowers.

The thin-walled, staminal column, or stamen tube, arises from the flower’s center. The upper walls of the staminal column comprise fine filaments growing out from the column and ending in pollen encrusted anthers, which are male organs for generating pollen. The staminal column encloses a white style that branches at the column’s tip. The style’s branches are topped with stigma pads, which are female organs for accepting pollen.

Hibiscus ‘Blue River II’ thrives in moist, sunny environments. Preferred soil is acidic, with a pH level that is lower than 7.0. Yet, the stunning cultivar tolerates ordinary garden soil and partial shade.

'Blue River II' hibiscus enlivens private and public landscapes. The tall, shrubby cultivar’s large, showy, pure white flowers contrast pleasantly and vividly with blue-tinged, large green leaves.

Walters Gardens, Inc., a leading North American wholesale perennial grower based in Zeeland, southwestern Michigan, suggests 'Caesar’s Brother' Siberian iris (Iris sibirica ‘Caesar’s Brother’) and an ornamental grass, 'Cheyenne Sky' switchgrass (Panicum virgatum Prairie Winds® ‘Cheyenne Sky’), as companion plants for sharing niches with hibiscus ‘Blue River II.’

The Chicago Botanic Garden’s five-acre Evening Island features ‘Blue River II’ in the company of Cleome ‘Sparkler White’ (Cleome hassleriana ‘Sparkler White’) and ‘Shenandoah’ switchgrass (Panicum virgatum ‘Shenandoah’). Scots pine (Pinus sylvestris) and the Theodore C. Butz Carillion Tower effectively frame the showy, white floral abundance of hibiscus ‘Blue River II.’

'Blue River II' hibiscus was introduced by Dr. Harold F. Winters,  a research horticulturist in the Crop Research Division at the U.S.D.A. (U.S. Department of Agriculture) Agricultural Research Service in Beltsville, southern Maryland. The cultivar’s name derives from the population of halberdleaf rosemallow that the horticulturist found growing along southern Oklahoma’s Blue River. As a tributary of the Red River that flows from northern Texas and southwestern Oklahoma eastward and southward through Louisiana, the Blue River belongs to the Mississippi River watershed.

‘Blue River II’ hibiscus attests to the visual appeal of large, showy white flowers and blue-tinged, large green leaves.

Hibiscus ‘Blue River II’ (left foreground), with Cleome ‘Sparkler White,’ Panicum virgatum ‘Shenandoah’ and Pinus sylvestris (center, right background); Theodore C. Butz Carillon Tower (left background) on Evening Island, Chicago Botanic Garden, July 25, 2016: K M (cultivar413), CC BY 2.0, via Flickr

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Hibiscus moscheutos ‘Kopper King’: K M (cultivar413), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/131880272@N06/22105530525/

Hibiscus ‘Blue River II’ in the company of Cleome ‘Sparkler White,’ Evening Island, Chicago Botanic Garden, July 25, 2016: K M (cultivar413), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/131880272@N06/28692932491/

Hibiscus ‘Blue River II’ (left foreground), with Cleome ‘Sparkler White,’ Panicum virgatum ‘Shenandoah’ and Pinus sylvestris (center, right background); Theodore C. Butz Carillon Tower (left background) on Evening Island, Chicago Botanic Garden, July 25, 2016: K M (cultivar413), CC BY 2.0, via Flickr @ https://www.flickr.com/photos/131880272@N06/28154907193/

For further information:

“Blue River Hibiscus Hibiscus x ‘Blue River.’” Berry Nurseries > Perennials > Hibiscus.
Available @ http://www.berrynurseries.com/index.cfm/fuseaction/plants.plantDetail/plant_id/777/index.htm

“Blue River II Hibiscus.” Nature Hills Nursery Inc. > Perennials > Hibiscus.
Available @ https://www.chicagobotanic.org/downloads/planteval_notes/no4_hibiscus.pdf

“Hardy Hibiscus, Rose Mallow, Swamp Mallow ‘Blue River II’ Hibiscus moscheutos.” Dave’s Garden > Guides.
Available @ http://davesgarden.com/guides/pf/go/40888/

Hawke, Richard G. “Plant Evaluation Notes Hibiscus moscheutos Cultivars and Horticultural Hybrids.” Chicago Botanic Garden. December 1993.
Available @ https://www.chicagobotanic.org/downloads/planteval_notes/no4_hibiscus.pdf

“Hibiscus ‘Blue River II.’” Missouri Botanical Garden > Gardens & Gardening > Your Garden > Plant Finder.
Available @ http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=p320

“Hibiscus ‘Blue River II.’” Perennial Resource > Perennial Encyclopedia.
Available @ http://www.perennialresource.com/encyclopedia/view/?plant=422

“Hibiscus ‘Blue River II.’” Walters Gardens Inc. > Perennial Database.
Available @ http://www.waltersgardens.com/plants/view/?plant=422

Marriner, Derdriu. "Crimsoneyed Rosemallow (Hibiscus moscheutos) Has White to Red Flowers." Earth and Space News. Saturday, July 23, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/07/crimsoneyed-rosemallow-hibiscus.html

Ronayne, Michael. “Heirloom Cold-Hardy Hibiscus Availability.” Dave’s Garden > Communities > Forums > Hibiscus. Sept. 25, 2009.
Available @ http://davesgarden.com/community/forums/t/1041872/#b

Winters, Harold F. “Our Hardy Hibiscus Species as Ornamentals.” Economic Botany, vol. 24, no. 2 (April-June 1970): 155-164.
Available @ http://www.jstor.org/stable/4253137?seq=1#page_scan_tab_contents
Available @ http://link.springer.com/article/10.1007%2FBF02860595