Cornus kousa tree designated ‘Rutpink’

Abstract

A new Cornus kousa cultivar that is clearly distinguished by its floriferous display of showy, dark-pink floral bracts, attractive dark-green foliage, high level of winter hardiness, and tolerance of the incitants of powdery mildew.

Claims

1. A new and distinct cultivar dogwood tree, substantially as herein shown and described, comprising an advanced generation seedling of Cornus kousa with dark-pink colored floral bracts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) This new cultivar of dogwood is illustrated by the accompanying digital photographs, depicting defining characteristics of the plant by the best possible color representation using digital color photography. All color references herein are measured against said Royal Horticultural Society (R.H.S.) Colour Chart (1966). Colors are approximate as individual color depends on horticultural practices such as light level, temperature, and fertilization rate, among others.

(2) FIG. 1 shows four images of a dogwood tree of the present invention at peak floral display after 7 growing seasons. Multiple images are shown to present the different floral bract color displays depending on the level of sunshine, distance from tree, and angle of viewing. From left to right top to bottom: (A) photograph taken from ground level on a bright, sunny day; (B) photograph taken from ground level on a cloudy day; (C) photograph taken at a distance of 8 meters from tree on a bright, sunny day; and (D) photograph taken from an elevated position (4 meters) on bright, sunny day.

(3) FIG. 2 shows four images representing close-up views of individual flower heads at peak ornamental display or shortly after. Note that the images show the distinctly acuminate floral bracts. From left to right top to bottom: (A) photograph taken in full sun on date of peak floral display prior to true flowers opening; (B) photograph taken out of direct sunlight on date of peak floral display; (C) photograph taken out of direct sunlight and next to R.H.S. Colour Chart card Red Group 54 for bract color comparison; and (D) photograph taken several days after peak floral display. Floral bracts fade to a lighter pink color once true flowers are open.

(4) FIG. 3 shows two digital images that represent the high density of flower heads per branch, which is a defining characteristic of ‘Rutpink’. The top image (A) was taken on a bright, sunny day at peak floral display. The bottom image (B) was taken on a cloudy day several days after true flowers opened. Note in the second image the floral bracts are slightly wider and the color is a lighter pink.

(5) FIG. 4 shows two digital images that represent the color and shape of mature fruit, which is consistent with the species. The top image (A) shows fruit that have just reached maturity. The lower image (B) shows older fruit that are beginning to senesce (soften), as well as a typical representation of fall leaf color.

BOTANICAL DESCRIPTION OF THE INVENTION

(6) Form: Tree. Growth habit: Dense tree branched low to ground with upright branches which form a rounded, but spreading, head. Vigorous but compact, and slightly taller than wide. Height: 3.20 meters at 7 years. Spread: 2.50 meters at 7 years. Plant vigor is similar to the species. Cold hardiness: The original seedling, and five grafted propagules thereof, have suffered no visible winter injury to vegetative or floral buds during the 6 and 2 winters since 2009 and 2013, respectively, that the plants have been under test in the field at New Brunswick, N.J., in USDA Plant Hardiness Map Zone 6a (−5 degree. to −10 degree F.). Resistance to insects and diseases: No evidence of insect problems has been observed on the original seedling, or its propagules, in the years the plants have been under test in New Jersey, Tennessee, and Oregon. An inconsequential amount of powdery mildew was observed on the original seeding plant in the year 2012 and 2014 in New Jersey and a small amount in 2014 in Tennessee on late season vigorous growth with none reported from Oregon. No evidence of susceptibility to Dogwood anthracnose or common dogwood borer has been presented. Trunk: Circumference of the trunk at 10 cm above the soil level was 29 cm after 7 growing seasons. Texture: Smooth, although some parts sandpaper rough due to presence of lenticels. Color of bark on trunk and main scaffold branches: Closest to 197A and 197B Greyed Green Group. Younger stems (1 and 2 years) closest to 200 C and 200 B Brown Group. Three-year-old branches closest to 197A and 197B Greyed Green Group and sandpaper rough due to the presence of lenticels (average 15-20 per cm.sup.2). Lenticels are closest to 156 B Greyed White Group. Size of lenticels is 1.0-2.0 mm long by 0.3 mm-0.4 mm wide. Lenticels are present on younger stems but are less than 1.0 mm long, same color. Branches: Crotch angle 35-55 degrees for large, major branches, but 45-70 degrees for subsequent smaller branches.

FOLIAGE

(7) Leaf arrangement: Opposite. Leaf size: Lamina. Average length.—96.7 mm (range 76-115; n=50). Average width.—55.8 mm (range 41-76, n=50), the widest point being a little more than half-way down from the tip. Petiole: Average length 6.4 mm (range 3-12 mm, n=50). Average diameter 1.3 mm (Range 1.1 mm-1.5 mm) n=50. Shape: Ovate/elliptic. Tip: Acuminate. Base: Rounded. Number of pairs of veins: 4 to 5. Margin: Moderately wavy with some leaves slightly folded towards adaxial side along mid vein. Texture: Adaxial surface is smooth. The abaxial surface is slightly fuzzy due to many minute trichomes on the blade and tufts of longer, thin hairs in clumps along the midrib and the secondary veins, especially at the junctures of the midvein and 4.sup.th and 5.sup.th pairs of secondary veins. Quantity: Densely foliaged. (See FIG. 1 A-D). Coloration: Solid. Mature leaf color: Adaxial.—Closest to 137A-B Green Group. Abaxial.—Closest to 138 B Green Group. The color of the lower one third of the mid vein on the adaxial side is 59 A Red-purple group. The same color also extends to the lower one third of the 4th or 5th secondary veins closest to the petiole. The color of the mid vein on the abaxial side is 160 D Greyed Yellow group with most secondary veins 59 A Red-Purple Group. Petiole.—Closest to 59 A Red Purple group. Immature leaf color: Adaxial.—Leaf surface areas closest to the veins are 144 A Yellow Green Group and in the regions between veins 187 A to 187 B Greyed Purple group. Veins are 59 A Red-Purple Group. Abaxial.—Mostly 146 C Yellow-green group with some interveinal splotches of 187 A Greyed Purple Group. Petiole is closest to 59 A Red-purple group. Autumn foliage color (mid-October), New Brunswick, New Jersey. Adaxial surface.—Most leaves 137A Green Group but mottled with other colors (mostly 187A Greyed-Purple Groups, 183A Greyed-Purple Group, 53A Red Group, 46A Red Group, 43A Red Group, and 9A Yellow Group). Abaxial surface.—138A Green Group. Leaf color is dependent on many environmental factors such as soil type, exposure to sun, air temperature, day length, available water and nutrients. Thus, leaf color may vary from one area to another.

INFLORESCENCE

(8) Location where observations were made: New Brunswick, New Jersey. Type of inflorescence: Flower head. Dense, rounded mound. Peduncle size (late May at time of anthesis): Average length (n=50): 78.7 mm cm (range=63 mm to 110 mm). Average width (n=20): 1.4 mm (range=1.2 cm-1.7 cm).

FLORAL BRACTS

(9) Number: Four (two opposing pairs, lower and upper). Size of floral bracts at time of floral period late May to early June.

(10) TABLE-US-00001 TABLE 1 Lower floral bract dimensions; n = 50 for all Lower bract measurements Average length Average Width Involucral spread (mm) (mm) (mm) 67.3 35.2 134.5 n = number of measurements.

(11) TABLE-US-00002 TABLE 2 Upper floral bract dimensions; n = 50 for all Upper bract measurements Average length Average Width Involucral spread (mm) (mm) (mm) 66.4 31.9 133.6 n = number of measurements. The average length of the lower and upper bracts is very similar in size with the lower bracts being just slightly larger on average. The average width of the lower bracts is consistently larger than the upper bract. Bract length and width will vary slightly from year-to-year based on environmental conditions and flower head numbers within the tree canopy, but the relationship between the size of the upper and lower bracts and the ratio of length to width across all bracts remains consistent. Shape: The individual floral bracts are distinctly acuminate with their apices terminating in a long, thin point. They are obtuse to rounded at their base. For most flower heads, bracts overlap their adjacent partner bract less than 10% of their total width at anthesis. Younger bracts show no overlap. Color: At peak of floral display (approximately May 28 to June 2 in New Brunswick, N.J.) in full sun exposure: Adaxial.—Closest to and in between 54 A and 54 B Red Group, most being 54 B. Abaxial.—Closest to 51 C Red Group with some visible veins the color of 51 B Red group. Peduncle of flower head at peak floral display is 144 C Yellow Green group. Floral bract color lightens (closest to 55 D Red Group) after anthesis and prior to dropping of the bracts. Flower description: Very floriferous. Single flowers arranged in compact, dense heads subtended by the large floral bracts. The average number of true flowers per flower head is 42, ranging from 38 to 46 (n=20). No observed fragrance. Flowers are not persistent. Floral display of the involucral bracts typically lasts about three weeks depending on weather conditions. Flowering habit: Anthesis of the tiny, relatively inconspicuous true flowers generally begins around the time of peak ornamental display of the floral bracts (approximately May 28 to June 2 in New Brunswick, N.J.). The color of the floral bracts lightens after anthesis.

REPRODUCTIVE ORGANS

(12) Stamens per flower: 4. Filament: Length.—Approximately 2.75 mm (n=4). Width.—Approximately 0.28 mm (n=4). Color.—155B White Group. Anther: Length.—Approximately 0.4 mm (n=4). Width.—Approximately 0.81 mm (n=4). Color: 162A Greyed-Yellow Group. Pollen: Color of freshly dehisced pollen is approximately 158 A Yellow white group. Style: Height.—Approximately 1.5 mm (n=4). Width.—Approximately 0.3 mm (n=4). Color.—144 C Yellow-Green Group. Stigma: Height.—Approximately 0.25 mm (n=4). Width.—Approximately 0.5 mm (n=4). Color.—144 C Yellow-Green Group. All figures are based on an average of the 4 measurements.

FRUIT

(13) Flower head with mature fruit. Fruits are 2-celled, typically 1-seeded, fleshy drupes that form a mounded, raspberry-like syncarp averaging 23.2 mm in length, 22.3 mm in width, and 21.0 mm in height (n=56). The many ovaries are enclosed in a fleshy, rounded mass typical for fruit of Cornus kousa. The exterior of the aggregate fruit is fairly smooth except for the dried floral parts at the tip of each individual drupe (the dried remains of the sepals and the persistent style and stigma). Fruit color varies from green to yellow to orange to pink as the fruit matures and finally to 46A to 42C Red Group. Fruits ripen in late August and persist for around 6 weeks. Seed: Color when dry.—Closest to 165 C to 165 D Greyed Orange Group. Size.—Average 6.4 mm length, 4.8 mm width, and 3.6 mm in thickness (n=40). Shape.—Typical for Cornus kousa. Average number of seeds per fruit is 16 (n=36).