SMHMTAU

Hydrangea

Variety Description

Variety used for comparison: 'Robert' (Let's Dance Moonlight)

Summary: The leaf blade of 'SMHMTAU' is broader than the leaf blade of 'Robert'. The shape of the base of the leaf blade of 'SMHMTAU' is rounded whereas the base of the leaf blade of 'Robert' is obtuse. The inflorescence of 'SMHMTAU' is shorter than the inflorescence of 'Robert'. The calyx of the sterile flower of 'SMHMTAU' is smaller in diameter than the calyx of the sterile flower of 'Robert'. When newly open, the colour of the inner side of the sepal from the sterile flower of 'SMHMTAU' is yellow to yellow green whereas the sepal from the sterile flower of 'Robert' is yellow green. When fully open, the colour of the inner side of the sepal from the sterile flower of 'SMHMTAU' is blue pink with white at the base whereas the sepal from the sterile flower of 'Robert' is lighter blue pink with white at the base.

Description:

PLANT: non-climbing type, upright growth habit
STEM: no fasciation, green, white lenticels

LEAF BLADE: no lobing, ovate and elliptic shape, short to medium length of tip, rounded base, medium depth of incisions of margin, no variegation, medium green on upper side, medium glossiness on upper side, medium to strong degree of blistering

FLOWERING: begins mid-season
INFLORESCENCE: globular shape, inconspicuous or slightly conspicuous fertile flowers
STERILE FLOWER: single type, strong degree of overlapping of sepals
STERILE FLOWER SEPAL: no incisions of margin on all sepals, when flower is newly open main colour of inner side is yellow to yellow green (RHS 2B-C), when flower is fully open main colour of inner side is blue pink (closest to RHS 63B) with white (RHS NN155D) at base, when flower is aged main colour of inner side is blue pink (closest to RHS 63B), no secondary colour of inner side
FERTILE FLOWER: inner side of petal is pink

Origin & Breeding History: 'SMHMTAU' was bred and developed by the breeder, Timothy D. Wood, of Spring Meadow Nursery, Inc. in Grand Haven, Michigan, USA. It originated from a controlled cross that occurred in June 2008, in Grand Haven, between the Hydrangea macrophylla variety 'Robert', as the female parent, and the H. macrophylla variety 'ES1', as the male parent. 'SMHMTAU' was selected in July 2010 for its compact plant growth habit, strong stems, richly coloured sepals, ability to rebloom, and ease of shifting colour of the sterile sepals to blue with aluminum sulfate treatments. Asexual reproduction of 'SMHMTAU' by softwood cuttings was first conducted in July 2010, in Grand Haven, Michigan, USA.

Tests & Trials: The comparative trial of 'SMHMTAU' was conducted in a polyhouse during the spring of 2015 at BioFlora Inc. in St. Thomas, Ontario. It included a total of 10 shrubs each of the candidate and reference variety. All shrubs were grown from rooted cuttings that were each transplanted into an 11.4 litre container on September 20, 2013 for the candidate variety and on June 19, 2013 for the reference variety. Observations and measurements were taken from 10 shrubs or parts of shrubs of the candidate and reference variety on May 28, 2015. All colour determinations were made using the 2007 Royal Horticultural Society (RHS) Colour Chart.

Comparison tables for 'SMHMTAU' with reference variety 'Robert'

Leaf blade width (cm)

Inflorescence height (cm)

Diameter of calyx of sterile flower (cm)

Colour of inner side of sepal from sterile flower (RHS)

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Hydrangea: 'SMHMTAU' (left) with reference variety 'Robert' (right)

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Hydrangea: 'SMHMTAU' (left) with reference variety 'Robert' (right)

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Hydrangea: 'SMHMTAU' (left) with reference variety 'Robert' (right)