A new and distinct Hydrangea cultivar named ‘NCHA2’ is disclosed, characterized by large, mop-head inflorescences with prevalent sterile flowers and large, dark pink sepals. Plant habit is compact, and plants are triploid. The new variety is a Hydrangea normally produced as an outdoor garden or container plant.

Latin name of the genus and species: The Latin name of the novel plant variety disclosed herein isHydrangea arborescens.

Variety denomination: The seedling ofHydrangea arborescensdisclosed herein has been given the varietal denomination ‘NCHA2’.

BACKGROUND OF THE INVENTION

The present invention comprises a new and distincthydrangeacultivar hereinafter referred to by the cultivar name ‘NCHA2’. This newhydrangeawas developed through a breeding program at North Carolina State University, Mills River, N.C. ‘NCHA2’ was selected from a population of seedlings that resulted from a cross between the pollen parent,Hydrangea arborescensH2008-143-001 (unpatented) and the seed parentHydrangea arborescensH2009-067-039 (unpatented). SeeFIG. 1for a complete pedigree. The first asexual propagation of ‘NCHA2’ was carried out in July 2012 by rooting stem cuttings at the North Carolina State University, Mountain Horticultural Crops Research Station, Mills River, N.C. and has been asexually reproduced repeatedly by vegetative cuttings over a three year period. ‘NCHA2’ roots readily from softwood cuttings treated with a basal dip of 2,500-5,000 ppm indole butyric acid (potassium salt) in water. ‘NCHA2’ has been found to retain its distinctive characteristics through successive asexual propagations.

SUMMARY OF THE INVENTION

The following are the unique combination of characteristics of this new cultivar when grown under standard horticultural practices at North Carolina State University, Mountain Horticultural Crops Research Station, Mills River, N.C.1. Large, mop-head inflorescences (i.e., a hortensia flower form) with prevalent sterile flowers and large, dark pink sepals.2. Triploid cytotype.3. Compact form.

COMPARISON WITH PARENT VARIETIES

‘NCHA2’ is similar to the seed parent in most horticultural characteristics, however, the new variety differs in the following:1. The new variety has a darker and stronger red-purple sterile sepal color.2. The new variety has as different ploidy level, 3.6 pg, compared to 5.2 pg of the seed parent.

‘NCHA2’ is similar to the pollen in most horticultural characteristics, however, the new variety differs in the following:1. The new variety has a different red-purple sterile sepal color.2. The new variety has a different ploidy level, 3.6 pg, compared to 2.7 pg of the pollen parent.

COMPARISON WITH COMMERCIAL CULTIVARS

Table 1 shows distinguishing characteristics between ‘NCHA2’ and other commercially available cultivars ofHydrangea arborescens. Hydrangea arborescens‘NCHA2’ has a unique combination of traits including a mophead inflorescence, large pink sepals, a compact form, and a triploid cytotype.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of the botanical characteristics of the new and distincthydrangeavariety plant known by the denomination ‘NCHA2’. The detailed description was taken on a three-year-old field-grown plant in Mills River, N.C. in 2014. All colors cited herein refer to The Royal Horticultural Society Colour Chart (The Royal Horticultural Society (R.H.S.), London, 2001 Edition). Where specific dimensions, sizes, colors, and other characteristics are given, it is to be understood that such characteristics are approximations or averages set forth as accurately as practicable.

Technical Description of the Variety

OTHER CHARACTERISTICS

Fruit/seed set: Seeds are minute, dust-like. Color not accurately measured with R.H.S. chart.Disease and insect resistance: No significant disease or insect pests have been observed.Cold hardiness: At least USDA zone 6b; testing has not been completed in colder zones.Genome size: Flow cytometry was conducted to determine DNA content which is directly correlated with ploidy among closely related taxa. Holoploid, 2C DNA content was determined on newly expanded leaf tissue. Nuclei were extracted, stained with 4′,6-Diamidino-2-phenylindole (DAPI), and analyzed (minimum of 5,000 nuclei per sample) using a flow cytometer (PA-I, Partec, Münster, Germany).Pisum sativumL. ‘Ctirad’, with a known genome size of 8.75 pg was used as an internal standard. 2C DNA content for ‘NCHA2’ was 3.9 pg, approximately 1.5 times the DNA content of a diploid (e.g., ‘NCHA1’), and consistent with being a triploid as would be expected from an interploid cross between diploid and tetraploid parents (see Table 1).