Helleborus ‘HGC Joshua’ Has White to Light Green Flowers

Summary: Helleborus ‘HGC Joshua,’ a Christmas rose (Helleborus niger) cultivar by German breeder Joseph Heuger, has white to light green flowers.

side view of flower of Helleborus ‘HGC Joshua’ in images included in Joseph Heuger’s patent application, filed Feb. 17, 2006, with the United States Patent and Trademark Office (USPTO): color scans via Plant Patents Image Database, Engineering & Physical Science Library (USPTO designation: College Park Patent & Trademark Resource Center), University of Maryland, CC BY 2.0, via University of Maryland’s Plant Patents Image Database @ http://www.lib.umd.edu/plantpatents/binaries/17900/pp17957.pdf

Helleborus ‘HGC Joshua,’ a Lenten rose, or black hellebore (Helleborus orientalis), cultivar by German hellebore hybridizer Joseph Heuger, has white to light green flowers and dark green leaves.

On Feb. 17, 2006, Heuger filed an application with the United States Patent and Trademark Office for a patent for Helleborus ‘HGC Joshua.’ Primary examiner Kent Ball and assistant examiner Annette H. Para reviewed Heuger’s application. On Aug. 28, 2007, the U.S. Patent and Trademark Office assigned plant patent number 17,957 to Helleborus ‘HGC Joshua.’

‘HGC Joshua’ has its origins in a breeding program conducted in December 1999 by the inventor. Unnamed, unpatented female and male Helleborus niger seedlings were cross-pollinated in a controlled environment at Heuger’s family nursery, Heuger Gartenbaubetriebe, in Glandorf, Lower Saxony state, northwestern Germany.

Heuger discovered and selected the flowering plant now known as Helleborus ‘HGC Joshua’ from among the cross-pollinated parents’ progeny. ‘HGC Joshua’ exhibited distinctive traits of a compact, upright habit; attractively colored flowers and leaves; an early and long flowering season.

Heuger’s application describes approximately 1-year-old plants that were grown in 13-centimeter (5.11-inch) containers in a glass-covered greenhouse in winter and in an outdoor summer nursery. Production temperatures in the greenhouse registered about 12 degrees Celsius (53.6 degrees Fahrenheit) during the day and ranged from about 2 degrees to about 12 degrees C (35.6 to 53.6 degrees F) during the night. Temperatures in the outdoor nursery ranged from about 5 to 34 degrees C (41 to 93.2 degrees F) during the day and from about 1 to about 25 degrees C (33.8 to 77 degrees F) during the night.

When planted in the ground, Helleborus ‘HGC Joshua’ has a temperature tolerance that ranges from about minus 10 to about 36 degrees C (14 to 96.8 degrees F).

Heuger’s Helleborus niger cultivar displays a moderately vigorous growth habit. Its compact, upright form features basal leaves and single flowers. Height ranges are from about 8 to 12 centimeters (3.14 to 4.72 inches). Spread, or width, ranges from about 20 to 25 centimeters (7.87 to 9.84 inches).

Basal foliage is palmately compound. Five to seven leaflets radiate from each leaf’s petiole, the stalk attaching the leaf to the stem.

Lanceolate, or lance-shaped, leaflets have serrated margins. Upper and lower surfaces have textures described hairlessly smooth, or glabrous, and leathery.

Leaflet length ranges from about 3.5 to 6 centimeters (1.37 to 2.36 inches). Width range is from about 1.5 to 3 centimeters (0.59 to 1.18 inches).

Upper surfaces of developing and fully expanded leaflets are dark green (close to Royal Horticultural Society colour chart color 147A). Veins are brown green (RHS 146B).

Lower surfaces of developing and fully expanded leaflets are brown green (close to RHS 147B). Veins are brown green (RHS 146C).

Petioles have lengths of about 1 to 8 millimeters (0.039 to 0.314 inches). Diameter range is from about 2 to 2.5 millimeters (0.078 to 0.098 inches).

Upper and lower surfaces of petioles are hairlessly smooth, described as glabrous.

Upper and lower surfaces of petioles are brown green (RHS 146C to 146D). Random spots are dark brown (RHS 200A to 200B).

Helleborus ‘HGC Joshua’ has an early and long natural flowering season. Intermittent flowering occurs from November to February in Germany. A freely flowering habit yields about 10 to 15 developing flowers per plant over the blooming period. On the plant, flowers last about 10 days.

Single rounded flowers are each borne in a single arrangement on upright peduncles, or floral stems. Flowers have a slight fragrance and mostly face uprightly to outwardly.

Ovoid, or egg-shaped, buds are about 1.2 centimeters (0.47 to inches) in height. Bud diameter is about 8 centimeters (3.14 inches).

Each flower typically comprises five to eight sepals, arranged in a single whorl. Sepal length ranges from about 2.5 to 3 centimeters (0.98 to 1.18 inches). Sepal width is about 2 centimeters (0.78 inches).

Broadly ovate, or egg-shaped, sepals have smooth margins, described as entire. Textures of upper and lower surfaces are described as glabrous, with hairless smoothness, and satiny.

Upper and lower surfaces of fully expanded sepals are bright white (more than RHS 155D), with light green (RHS 144C) toward the base. With development, coloring approaches light green (close to RHS 144B to 144C).

Peduncles are strong, with a mostly upright orientation. Peduncle texture is hairlessly smooth, described as glabrous.

Peduncle length ranges from about 10 to 25 centimeters (3.93 to 9.84 inches). Diameter range is from about 2 to 5 millimeters (0.078 to 0.19 inches).

Peduncle coloring is light green (RHS 145B), with brown purple (RHS 178A) spots.

Heuger’s 2015-2016 hellebore catalog lists ‘HGC Joshua’℗ as available in containers sized 11 to 13 centimeters (4.33 to 5.11 inches). Growth is described as compact. Selling is targeted to begin in mid-November.

The takeaway for Helleborus ‘HGC Joshua’ is the early, long blooming period, from late autumn through winter, that Heuger’s Christmas rose cultivar enjoys and the pleasing colors that Joshua’s white to light green flowers and dark green leaves contribute to fresh cut arrangements and to in-ground and potted garden spaces.

Helleborus Joshua, German hellebore hybridizer Joseph Heuger's Christmas rose cultivar, shows well in floral displays: CowellsGardenCentre @CowellsgCentre via Twitter Dec. 11, 2011

Acknowledgment

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

Image credits:

side view of flower of Helleborus ‘HGC Joshua’ in images included in Joseph Heuger’s patent application, filed Feb. 17, 2006, with the United States Patent and Trademark Office (USPTO): color scans via Plant Patents Image Database, Engineering & Physical Science Library (USPTO designation: College Park Patent & Trademark Resource Center), University of Maryland, CC BY 2.0, via University of Maryland’s Plant Patents Image Database @ http://www.lib.umd.edu/plantpatents/binaries/17900/pp17957.pdf

Helleborus Joshua, German hellebore hybridizer Joseph Heuger's Christmas rose cultivar, shows well in floral displays: CowellsGardenCentre @CowellsgCentre via Twitter Dec. 11, 2011, @ https://twitter.com/CowellsgCentre/status/145810543641493504

For further information:

Burrell, C. Colston; Judith Knott Tyler. Hellebores: A Comprehensive Guide. Portland OR: Timber Press, 2006.

Burrell, C. Colston; Judith Knott Tyler. “Not Your Mother’s Hellebores: A New Look at Species and Hybrids (Part 2).” Pacific Horticulture magazine. January 2008.
Available @ http://www.pacifichorticulture.org/articles/not-your-mothers-hellebores-part-2/

CowellsGardenCentre @CowellsgCentre. "A canny cracking Christmas combo - Skimmia 'Temptation' & Helleborus 'Joshua.' Twitter. Dec. 11, 2011.
Available @ https://twitter.com/CowellsgCentre/status/145810543641493504

“Hellebore (Helleborus niger Gold Collection® Joshua).” The National Gardening Association > Plants Database > Hellebores.
Available @ http://garden.org/plants/view/586778/Hellebore-Helleborus-niger-Gold-Collection-Joshua/

“Helleborus Plant Named ‘HGC Joshua.’” United States Patent and Trademark Office > Program in Word (PIW). Aug. 28, 2007.
Available @ http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=PP017957

“HGC Joshua’℗.” Heuger > Katalog Helleborus 2015-2016.
Available @ http://www.heuger.com/fileadmin/lookbook/page5.html#/14

International Union for the Protection of New Varieties of Plants. “Document TGP/14: Glossary of Technical, Botanical and Statistical Terms Used in UPOV Documents. Section 2: Botanical Terms: Subsection 3: Color: (2): Color Names for the RHS Colour Chart.” UPOV (Union Internationale Pour la Protection des Obtentions Végétales). Dec. 9, 2006.
Available @ http://www.upov.int/edocs/mdocs/upov/en/tc_edc?2007/tgp_14_draft_1_section_2_3_2.pdf

Marriner, Derdriu. “Helleborus ‘COSEH 710’ Has Light Green Flowers With Reddish Pink Flushes.” Earth and Space News. Sunday, Nov. 13, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/11/helleborus-coseh-710-has-light-green.html

Marriner, Derdriu. “Helleborus ‘COSEH 740’ Has White Flowers and Dark Green Leaves.” Earth and Space News. Saturday, Nov. 26, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/11/helleborus-coseh-740-has-white-flowers.html

Marriner, Derdriu. “A Helleborus Plant Named ‘COSEH 700’ Has Large Light Green Flowers.” Earth and Space News. Saturday, Nov. 12, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/11/a-helleborus-plant-named-coseh-700-has.html

Marriner, Derdriu. “A Helleborus Plant Named ‘HGC Jacob’ Has White to Light Green Flowers.” Earth and Space News. Sunday, Nov. 6, 2016.
Available @ https://earth-and-space-news.blogspot.com/2016/11/a-helleborus-plant-named-hgc-jacob-has.html

“PP17957 -- Helleborus Plant Named ‘HGC Joshua.’” University of Maryland > Plant Patents Image Database.
Available @ http://www.lib.umd.edu/plantpatents/id/13922

Rice, Graham; Elizabeth Strangman. The Gardener’s Guide to Growing Hellebores. Newton Abbot, England: David and Charles, 2005.