Abstract:
A new and distinct cultivar of  Hydrangea arborescens  plant named ‘PIIHA-I’, characterized by its magenta to pink mophead inflorescences; dark green foliage; and upright, spreading growth habit.

Description:
GENUS AND SPECIES OF PLANT CLAIMED 
       [0001]      Hydrangea arborescens  L. 
       VARIETY DENOMINATION 
       [0002]    ‘PIIHA-I’ 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to a new and distinct cultivar of  Hydrangea arborescens,  a member of the Hydrangeaceae family, hereinafter referred to by its cultivar name ‘PIIHA-I’. 
         [0004]    This cultivar is grown primarily as an ornamental for landscape use. The cultivar originated as an open-pollinated seedling from a numbered selection, WF-03-03-01-07 (unpatented), of  Hydrangea arborescens  in a controlled breeding program to develop a pink mophead  Hydrangea arborescens  at Watkinsville, Ga. WF-03-03-01-07 is a seedling of  Hydrangea arborescens  that was derived from the cultivar ‘Wesser Falls’ (unpatented). 
         [0005]    ‘PIIHA-I’ has been asexually reproduced by softwood cuttings in Watkinsville, Ga. The characteristics of the cultivar have been stable and reproduced true-to-type in successive vegetative generations. 
       SUMMARY OF THE INVENTION 
       [0006]    ‘PIIHA-I’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with changes in light, temperature, soil and rainfall without, however, any variance in genotype. 
         [0007]    The following traits have been repeatedly observed and represent the unique characteristics of the new cultivar. In combination these characteristics distinguish ‘PIIHA-I’ from all other varieties in commerce known to the inventor. 1) Magenta to pink mophead inflorescences that hold the color for about 5 weeks. 2) Dark green foliage. 3) Upright, spreading growth habit. 
         [0008]    ‘PIIHA-I’ is distinguished from its female parent WF-03-03-01-07 by its mophead inflorescence, flower color, and foliage color. The male or pollen parent is unknown, but is one of several  Hydrangea arborescens  in the breeding program, all of which are unpatented. ‘PIIHA-I’ has magenta to pink mophead inflorescences, whereas WF-03-03-01-07 has pale pink to white lacecap inflorescences. ‘PIIHA-I’ also has darker green leaves than WF-03-03-01-07. 
         [0009]    There are no other pink mophead cultivars of  Hydrangea arborescens  known to the inventor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying illustrations show characteristics of the new cultivar in photographs as true to color as is reasonably possible to make in illustrations of this nature. 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  Hydrangea.    
           [0011]      FIG. 1  shows a mature inflorescence on ‘PIIHA-I’ in summer. 
           [0012]      FIG. 2  shows a comparison of ‘PIIHA-I’ (second from left) to other seedlings from the same open-pollination. 
           [0013]      FIG. 3  shows mature foliage in summer on ‘PIIHA-I’. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2001 Edition, except where general terms of ordinary dictionary significance are used. Plants used for the description were grown in 11.8 L containers under 50% shade under outdoor conditions at Watkinsville, Ga. Colors are described using The Royal Horticultural Society (R.H.S.) Colour Chart.
   Botanical classification: ‘PIIHA-I’ is a cultivar of  Hydrangea arborescens.      Parentage: The current variety is an open-pollinated progeny from a numbered selection of  Hydrangea arborescens,  WF-03-03-01-07 (unpatented).   Propagation: Vegetatively by stem cuttings.   Plant description: The claimed variety is an upright, spreading deciduous shrub. Freely branching. The plant is hardy in USDA Zones 3 to 9.
             Plant height.— about 90 cm.     Plant diameter.— about 90 cm. Side shoots range in length from about 15 to 30 cm.     Stems.— First year stems have a diameter of about 7 mm, a round shape.     Pubescence.— very fine.     Stem color.— close to 146C with some areas close to 181B.     Exfoliation.— on first year stems once mature, flaky and stringy. Second year stems have a diameter of about 1 cm and color close to 199B.     Internode length.— about 6 cm.     Vegetative buds.— Arrangement: opposite.     Shape.— ovoid.     Size.— about 3 mm in length and about 1 mm in width.     Color.— close to 146C.       
       Foliage description:
             Arrangement.— opposite, simple.     Size.— about 13.2 cm in length and about 9.6 cm in width.     Shape.— ovate, with acuminate apex, rounded or cordate base, and serrate margin.     Texture.— papery, soft above, rough below.     Color.— emerging leaves are close to 144C on the upper and lower surfaces; mature leaves on the upper surface are close to 147A, and close to 147C on the lower surface. Fall leaves develop a range of yellow colors.     Venation.— pinnate, veins are impressed into leaves and close to 146C.     Petiole size and shape.— about 6.7 cm in length and about 2 mm in diameter, rounded, grooved, glabrous.     Petiole color.— close to 181A above and 144A below.       
       Flower description:
             Flower type and arrangement.— Inflorescence is a corymb (mophead) about 12.5 cm in diameter and about 8 cm high. An inflorescence contains about 300 individual sterile florets and about 75 individual fertile flowers.     Inflorescence bloom period.— Summer. The inflorescence is effective for about 5 weeks.     Flower bud length.— about 2 mm.     Flower bud diameter.— about 2 mm.     Flower bud shape.— round.     Color.— close to 58A.     Peduncle.— about 1 cm in length, finely pubescent, and color is close to 181B.       
       Sepals:
             Arrangement/appearance.— sterile florets contain 3 to 5 (usually 4) sepals per floret.     Sepal length.— about 7 mm.     Sepal width.— about 5 mm.     Sepal shape and texture.— elliptical with acute apex, cuneate base, and entire margin.     Texture.— smooth with no pubescence.     Sepal color.— upper surface is close to 58A and the lower surface is close to 63A at peak flowering.       
       Petals:
             Arrangement/appearance.— fertile flowers have 5 petals per flower.     Petal length.— about 3 mm.     Petal width.— about 2 mm.     Petal shape and texture.— elliptical, with acute apex, cuneate base, and entire margin.     Texture.— smooth with no pubescence.     Petal color.— at peak of bloom the upper surface of the petals is close to 58A and the lower surface is close to 63A.       
       Stamens:
             Quantity.— usually 10 per flower.     Anthers.— about 1 mm in length and about 1 mm in width, close to 65D.     Filaments.— about 3 mm in length and about 0.5 mm in width, close to N155B.     Pollen.— close to N155B.       
       Pistils:
             Quantity/arrangement.— 1 per flower, superior.     Pistil length.— about 2 mm.     Pistil width.— about 1 mm.     Pistil color.— close to N155B.     Stigma.— usually 2 per pistil, round in shape and close to N155B.     Style.— about 2 mm in length, tubular in shape, close to N155B.       
       Fruit:
             Type and shape.— the capsule fruit is ovoid.     Length.— about 3 mm.     Width.— about 2 mm.     Color.— during early ripening is close to 146D and at maturity is close to 200D.     Quantity.— about 75 per infructescence.     Seeds.— round, about 0.5 mm in length and about 0.5 mm in width, close to 199B, and each capsule contains about 50 seeds.       
       Disease/pest resistance: Plants of the claimed  Hydrangea  cultivar grown in the garden have not been noted to be resistant to pathogens and pests common to  Hydrangea.