Hydrangea plant named ‘ILVOCLOU’

A new and distinct Hydrangea plant named ‘ILVOCLOU’ is disclosed, characterized by compact plants producing lace-cap inflorescences having light violet-blue sterile flowers with purple sepals and medium violet-blue fertile flowers. Plants produce attractive foliage and bloom abundantly. The new variety is a Hydrangea, normally produced as an ornamental plant.

Latin name of the genus and species:Hydrangea macrophylla.

BACKGROUND OF THE INVENTION

The newHydrangeacultivar is a product of a planned breeding program conducted by the inventors, at a commercial nursery in Melle, Belgium. The objective of the breeding program was to produce newHydrangeavarieties with compact habits and strong blooming beginning in the first year. The cross resulting in this new variety was made during Summer of 2003.

The seed parent is the unpatented varietyHydrangea serrata‘Bluebird’. The pollen parent is the unpatented varietyHydrangea macrophylla‘Mariesii Perfecta’. The new variety was identified as a potentially interesting selection in the Summer of 2007, at a commercial greenhouse in Melle, Belgium.

Asexual reproduction of the new cultivar ‘ILVOCLOU’ by vegetative soft wood cuttings was first performed during the Summer of 2016, at a commercial greenhouse in Melle, Belgium. Subsequent propagation has shown that the unique features of this cultivar are stable and reproduced true to type in6successive generations.

SUMMARY OF THE INVENTION

The cultivar ‘ILVOCLOU’ has not been observed under all possible environmental conditions. The phenotype may vary somewhat with variations in environment such as temperature, day length, and light intensity, without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘ILVOCLOU’ These characteristics in combination distinguish ‘ILVOCLOU’ as a new and distinctHydrangeacultivar:1. Compact plants.2. Lace-cap inflorescence.3. Sterile flowers colored light violet blue-with purple sepals.4. Fertile flower colors colored medium violet-blue.5. Abundant flowering.6. Attractive foliage.

PARENT COMPARISON

Plants of the new cultivar ‘ILVOCLOU’ are similar to plants of the seed parent varietyHydrangea serrata‘Bluebird’ in most horticultural characteristics, however, plants of the new cultivar ‘ILVOCLOU’ differ in the following;1. The new variety has more showy sepals than the seed parent.2. The new variety is a more compact plant than the seed parent.

Plants of the new cultivar ‘ILVOCLOU’ are similar to plants of the pollen parent varietyHydrangea macrophylla‘Mariesii Perfecta’ in most horticultural characteristics, however, plants of the new cultivar ‘ILVOCLOU’ differ in the following;1. The new variety has lighter green foliage than the pollen parent variety.2. The new variety has more showy sepals than the pollen parent.3. The new variety has a stronger flower color than the pollen parent.

COMMERCIAL COMPARISON

Plants of the new cultivar ‘ILVOCLOU’ can be compared to the varietyHydrangea macrophylla‘SMHMLDD’, U.S. Plant Pat. No. 25,105. These varieties are similar in most horticultural characteristics; however ‘ILVOCLOU’ differs in the following:1. The new variety has lighter green foliage than this comparator.2. The new variety is more floriferous than this comparator.3. The new variety is a more compact plant than this comparator.

DETAILED BOTANICAL DESCRIPTION

In the following description, color references are made to The Royal Horticultural Society Colour Chart 1996 except where general terms of ordinary dictionary significance are used. The following observations and measurements describe ‘ILVOCLOU’ plants grown in a commercial poly greenhouse in Grand Haven, Mich. under natural lighting. Measurements were taken during the July of 2015. The plants were about 4 years old planted in the ground. The growing temperature ranged from 5° C. to 27° C. Measurements and numerical values represent averages of typical plant types.Botanical classification:Hydrangea macrophylla‘ILVOCLOU’.

PROPAGATION

Time to initiate roots: Approximately 18 days at approximately 27° C.Time to produce a rooted young plants: Approximately 60 days at approximately 27° C.Root description: Fibrous. Free to moderately free root branching, fine roots. Roots mainly white, about RHS White 155D.Propagation method: Softwood cuttings.

PLANT

FOLIAGE

FLOWER

REPRODUCTIVE ORGANS

OTHER CHARACTERISTICS

Seeds and fruits: Moderate quantity of small dust like seeds. Less than 1 mm wide and 1 mm long. Colored near RHS Greyed-Brown N199A.Disease/pest resistance: Neither resistance nor susceptibility to normal diseases and pests ofHydrangeahave been observed.Temperature tolerance: USDA Zones 4 to 9.