<i>Helleborus </i>plant named ‘COSEH 5900’

Abstract

A new and distinct cultivar of Helleborus plant named COSEH 5900, characterized by its upright and mounded plant habit; vigorous growth habit; dark green-colored leaves; freely flowering habit; single white-colored flowers; and good garden performance.

Claims

1. A new and distinct Helleborus plant named COSEH 5900 as illustrated and described.

Description

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

(1) The accompanying colored photographs illustrate the overall appearance of the new Helleborus plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ slightly from the color values cited in the detailed botanical description which accurately describe the colors of the new Helleborus plant.

(2) The photograph on the first sheet (FIG. 1 of 2) is a side perspective view of a typical flowering plant of COSEH 5900 grown in a container.

(3) The photograph on the second sheet (FIG. 2 of 2) is a close-up view of typical flowers and leaves of COSEH 5900.

DETAILED BOTANICAL DESCRIPTION

(4) The aforementioned photographs and following observations, measurements and values describe plants grown during December in 17-cm containers in a glass-covered greenhouse in Glandorf, Germany and under cultural practices typical of commercial Helleborus production. During the production of the plants, day temperatures ranged from 12 C. to 32 C. and night temperatures ranged from 5 C. to 12 C. Plants were 14 months old when the photographs and the description were taken. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used. Botanical classification: Helleborus niger X Helleborus x hybridus COSEH 5900. Parentage: Female, or seed, parent.Unnamed selection of Helleborus niger, not patented. Male, or pollen, parent.Unnamed selection of Helleborus x hybridus, not patented. Propagation: Type.In vitro axillary meristem culture. Time to initiate roots, winter.About 55 days at temperatures about 12 C. Time to produce a rooted young plant, winter.About 170 days at temperatures ranging from 4 C. to 15 C. Root description.Thick to thin, fleshy; typically white to brown in color, actual color of the roots is dependent on substrate composition, water quality, fertilizer type and formulation, substrate temperature and physiological age of roots. Rooting habit.Low branching; sparse. Plant description: Plant and growth habit.Herbaceous perennial; upright and mounding plant habit with flowers held within and above the foliar plane; plant shape, roughly flattened globular; vigorous growth habit and moderate to rapid growth rate. Plant height, soil level to top of foliar plane.About 37 cm. Plant height, soil level to top of flowers.About 40.8 cm. Plant diameter (area of spread).About 45.7 cm. Leaf description: Arrangement.Leaves arranged in a basal rosette; leaves palmately compound with typically seven leaflets per leaf. Leaf length.About 18 cm. Leaf width.About 21.1 cm. Leaflet length.About 9.3 cm. Leaflet width.About 6.5 cm. Leaf shape.Palmate; reniform in outline. Leaflet shape.Obovate to broadly obovate. Leaflet apex.Acute to broadly acute. Leaflet base.Attenuate. Leaflet margin.Serrate; slightly undulate to non-undulate. Leaflet texture and luster, upper surface.Smooth, glabrous; leathery; slightly to moderately glossy. Leaflet texture and luster, lower surface.Smooth, glabrous; leathery; slightly glossy. Leaflet venation pattern.Pinnate. Leaflet color.Developing leaflets, upper surface: Close to NN137A; midvein distally, close to 183B. Developing leaflets, lower surface: Close to between 138A and 147B. Fully developed leaflets, upper surface: Darker than 147A; venation, close to 144B. Fully developed leaflets, lower surface: Close to 147B; venation, close to 145A to 145B. Petioles.Length: About 17.1 cm. Diameter: About 8 mm to 10 mm. Strength: Strong. Texture and luster, upper and lower surfaces: Smooth, glabrous; slightly to moderately glossy. Color, upper and lower surfaces: Close to 145A covered slightly to heavily with fine dots, close to 187A to 187D. Flower description: Flower shape and habit.Single rotate flowers; flowers slightly cupped; arranged solitary or in clusters with about four flowers each; freely flowering habit with about 22 flowers developing per plant; flowers face mostly outwardly to slightly nodding or slightly upright. Fragrance.None detected. Natural flowering season.Plants begin flowering about ten months after planting; plants flower from the late autumn into the winter in Germany. Flower longevity on the plant.About three to four months; sepals persistent, other flower parts are not persistent. Flower buds.Length: About 1.8 cm. Diameter: About 1.1 cm. Shape: Ovate. Texture and luster: Smooth, glabrous; matte. Color: Close to between 145D and 157B; proximally, close to 145C. Inflorescence height.About 8.7 cm. Inflorescence diameter.About 16.2 cm. Flower diameter.About 8.3 cm by 8.3 cm. Flower depth (height).About 3 cm. Petals.All petals are transformed into nectaries. Sepals.Quantity and arrangement: About five, arranged in a single whorl. Length: About 4.7 cm. Width: About 4.2 cm. Shape: Broadly ovate, slightly concave. Apex: Obtuse. Base: Truncate to rounded. Margin: Entire; not undulate. Texture and luster, upper surface: Smooth, glabrous; matte. Texture and luster, lower surface: Smooth, glabrous; slightly glossy. Color: When opening, upper and lower surfaces: Close to NN155A and proximally, close to 145B; venation, similar to lamina color. Fully opened, upper surface: Close to NN155B and proximally, close to 145A; venation, similar to lamina color; with development, close to 145B and proximally, close to 145A. Fully opened, lower surface: Close to 155C, towards the margins and apex, close to NN155B and proximally, close to 145A to 145B; venation, similar to lamina color; with development, close to 145B and proximally, close to 145A. Flower bracts.Quantity per flower: Typically one or two. Length: About 5.3 cm. Width: About 3.4 cm. Shape: Ovate to broadly ovate. Apex: Acute. Base: Truncate. Margin: Serrate; slightly undulate to non-undulate. Color, upper surface: Close to between NN137A and 147A; venation, similar to lamina. Color, lower surface: Close to 147B; venation, similar to lamina. Peduncles.Length: About 30 cm. Diameter: About 6 mm to 7 mm. Aspect: About 10 from vertical. Strength: Strong. Texture and luster: Smooth, glabrous; moderately glossy. Color: Close to 144B; moderately to heavily covered with fine dots, close to between 183B and 187C. Pedicels.Length: About 4.4 cm. Diameter: About 3.5 mm to 4 mm. Aspect: About 10 from peduncle axis. Strength: Moderately strong. Texture and luster: Smooth, glabrous; moderately glossy. Color: Close to 144B moderately to heavily covered with fine dots, close to 183D. Reproductive organs.Stamens: Quantity per flower: About 100. Filament length: About 1.8 cm. Filament color: Close to NN155B. Anther shape: Double and broadly reniform; basifixed. Anther size: About 2 mm by 2 mm. Anther color: Close to 150C. Pollen amount: Moderate. Pollen color: Close to 4D. Pistils: Quantity per flower: About six to twelve. Pistil length: About 9 mm. Stigma diameter: About 0.3 mm. Stigma shape: Club-shaped. Stigma color: Close to 150D. Style length: About 8 mm. Style color: Close to 181C. Ovary color: Close to 145C. Nectaries (transformed petals): Quantity per flower: About twelve. Length: About 1.3 cm. Diameter: About 5 mm. Shape: Tubular, flattened. Texture and luster, inner and outer surfaces: Smooth, glabrous; slightly glossy. Color, immature, inner and outer surfaces: Close to 144A, distally, close to N144B and proximally, close to 146C. Color, mature, inner and outer surfaces: Close to 144A, distally, close to N144A to N144B and proximally, close to 146C; with development, close to 144A, distally, close to N144A and proximally, close to 146C. Seeds and fruits.To date, seed and fruit development have not been observed on plants of the new Helleborus. Garden performance: Plants of the new Helleborus have been observed to have good garden performance and to tolerate rain, wind, high temperatures about 35 C. and to be suitable for USDA Hardiness Zones 5 through 9. Pathogen & pest resistance: To date, plants of the new Helleborus have not been observed to be resistant to pathogens and pests common to Helleborus plants.