Helleborus ‘HGC Silvermoon’ Has White to Light Green Flowers

Summary: Helleborus ‘HGC Silvermoon,’ a hybrid hellebore (Helleborus niger x H. sternii) by German breeder Joseph Heuger, has white to light green flowers.

side view of flower of Helleborus ‘HGC Silvermoon’ in images included in Joseph Heuger’s patent application, filed June 28, 2004, 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/15600/pp15639.pdf

Helleborus ‘HGC Silvermoon,’ a hellebore hybrid (Helleborus niger x Helleborus sternii) by German hellebore hybridizer Joseph Heuger, has white to light green flowers and dark green leaves.

On June 28, 2004, Heuger filed an application with the United States Patent and Trademark Office, for a patent for Helleborus ‘HGC Silvermoon.’ Primary examiner Kent Bell and assistant examiner Wendy C. Haas reviewed Heuger’s application. On March 8, 2005, the U.S. Patent and Trademark Office assigned plant patent number 15,639 to Helleborus ‘HGC Silvermoon.’

Helleborus ‘HGC Silvermoon’ has its origins in a planned breeding program conducted by the inventor in January 1999. A cross-pollination of an unnamed, unpatented female Christmas rose (Helleborus niger) seedling with an unnamed, unpatented male Helleborus x sternii seedling took place in a controlled environment at Heuger’s family nursery, Heuger Gartenbaubetriebe, in Glandorf, Lower Saxony state, northwestern Germany.

One of the parent seedlings, the male, is itself a hybrid. Helleborus x sternii, which honors British botanist and horticulturist Sir Frederick Claude Stern (April 18, 1884-July 10, 1967), is a cross of Corsican hellebore (Helleborus argutifolius) and blue-grey hellebore (Helleborus lividus).

Heuger discovered and selected the flowering plant now known as Helleborus ‘HGC Silvermoon’ from among the cross-pollinated parents’ offspring. Heuger noted the new cultivar’s distinctive traits of compact, mounded plant habit; attractively colored flowers and foliage; long blooming period. Propagation by divisions, begun in March 2001, demonstrated the retention and true reproduction of distinctive traits over successive generations.

Heuger’s patent application describes plants, at about 6 months of age, that were grown indoors in Glandorf during winter in 15-centimeter (5.9-inch) containers. Temperatures during production registered 18 degrees Celsius (64.4 degrees Fahrenheit) during the day and 14 degrees C (57.2 degrees F) during the night.

Helleborus ‘HGC Silvermoon’ has a temperature tolerance range of minus 10 to 36 degrees C (14 to 96.8 degrees F).

The growth habit for Helleborus ‘HGC Silvermoon’ is moderately vigorous. Its compact, mounded plant habit has basal leaves and single flowers. Plant height measures about 14 centimeters (5.51 inches). Spread, or width, measures about 30 centimeters (11.81 inches).

Basal foliage comprises palmately compound leaves. Three to five leaflets radiate from the leaf’s attachment point at the distal end of the petiole, or leaf stalk.

Leaflet lengths range from about 5 to 10 centimeters (1.96 to 3.93 inches). Widths range from about 2.5 to 4 centimeters (0.98 to 1.57 inches).

Lanceolate, or lance-shaped, leaflets have serrated margins. Upper and lower surfaces have a glabrous texture, with hairless smoothness.

Fully expanded leaflets display dark green (Royal Horticultural Society colour chart color 147A) upper surfaces. Veins are brown green (RHS 146B).

Lower surfaces of fully expanded leaflets are brown green (RHS 147B). Veins are brown purple (RHS 183A).

‘HGC Silvermoon’ has a lengthy blooming period. Intermittent flowering occurs from December to February in Glandorf. A freely flowering habit yields about 10 developed flowers per plant over the blooming period. On the plant, flowers last about 10 days.

Single rounded flowers, facing outward and upright, are borne in a single arrangement atop upright peduncles, or floral stems. Peduncles measure about 5 to 7 centimeters (1.96 to 2.75 inches) in length. Diameters range from about 3 to 5 millimeters (0.11 to 0.19 inches).

Peduncles, which have an upright orientation, are strong. Their glabrous texture is hairlessly smooth. Their color is light green (RHS 145A). A slight overlay of brown purple (RHS 187A) imbues peduncles with a burgundy cast.

Flower buds, which are ovoid, or egg-shaped, measure about 1.2 centimeters (0.47 inches) in height. Bud diameter is about 7 millimeters (0.27 inches). Bud color is light green (RHS 145D).

Flowers typically have five sepals, arranged in a single whorl. Petals, which are tiny, form inconspicuous nectaries.

Sepal length is about 3.5 centimeters (1.37 inches). Width measures about 3 centimeters (1.18 inches).

Broadly ovate, or egg-shaped, sepals have rounded apices, or tips. Entire margins are smooth and untoothed. The glabrous texture of upper and lower surfaces is satiny and hairlessly smooth.

The upper surfaces of fully expanded sepals are light green (RHS 149D). With development, coloring approaches light green (RHS 145B to 145C).

The lower surfaces of fully expanded sepals are light green (RHS 149D), with a slight overlay of brown purple (RHS 187A).

The takeaway for Helleborus ‘HGC Silvermoon’ is the showiness, especially during its lengthy winter blooming period, of the Heuger hellebore’s white to light green flowers, atop their burgundy-effect stems, in fresh cut arrangements and in container or in-ground garden spaces.

closeup of Helleborus ‘HGC Silvermoon’ flower in images included in Joseph Heuger’s patent application, filed June 28, 2004, 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/15600/pp15639.pdf

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 Silvermoon’ in images included in Joseph Heuger’s patent application, filed June 28, 2004, 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/15600/pp15639.pdf

closeup of Helleborus ‘HGC Silvermoon’ flower in images included in Joseph Heuger’s patent application, filed June 28, 2004, 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/15600/pp15639.pdf

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/

“Hellebore (Helleborus Gold Collection® Silvermoon).” The National Gardening Association > Plants Database > Hellebores.
Available @ http://garden.org/plants/view/185831/Hellebore-Helleborus-Gold-Collection-Silvermoon/

“Helleborus ericsmithii ‘HGC Silvermoon’ PP15639.” Perennial Resource > Perennial Encyclopedia.
Available @ http://www.perennialresource.com/encyclopedia/view/?plant=1984

“Helleborus Plant Named ‘HGC Silvermoon.’” United States Patent and Trademark Office > Program in Word (PIW). March 8, 2005.
Available @ http://pdfpiw.uspto.gov/.piw?PageNum=0&docid=PP0156139

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 210’ Has Large White Flowers and Sells as ‘HGC Joel’®.” Earth and Space News. Sunday, Jan. 8, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/01/helleborus-coseh-210-has-large-white.html

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. “Helleborus ‘HGC Double Surprise’ Has Purple-Spotted White Double Flowers.” Earth and Space News. Sunday, Jan. 22, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/01/helleborus-hgc-double-surprise-has.html

Marriner, Derdriu. “Helleborus ‘HGC Josef Lemper’ Has White Flowers and Dark Green Leaves.” Earth and Space News. Saturday, Jan. 28, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/01/helleborus-hgc-josef-lemper-has-white.html

Marriner, Derdriu. “Helleborus ‘HGC Lady Freckle’ Has Red Purple-Spotted White Flowers.” Earth and Space News. Sunday, Jan. 29, 2017.
Available @ https://earth-and-space-news.blogspot.com/2017/01/helleborus-hgc-lady-freckle-has-red.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

“PP15639 -- Helleborus Plant Named ‘HGC Silvermoon.’” University of Maryland > Plant Patents Image Database.
Available @ http://www.lib.umd.edu/plantpatents/id/11605

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