SMSMBK

Spirea

Variety Description

Variety used for comparison: 'Snow Storm'

Summary: The plants of 'SMSMBK' are larger with a longer leaf blade than the plants of 'Snow Storm'. The plants of 'SMSMBK' are adapted to survive to Canadian cold hardiness zone 4 whereas the plants of 'Snow Storm' are adapted to survive to Canadian cold hardiness zone 5.

Description:

PLANT: adapted to survive to Canadian cold hardiness zone 4, shrub type, upright to spreading growth habit, dense branching, medium density of foliage

CURRENT SEASON SHOOT: very light yellow green
SHOOT: absent to very sparse pubescence, round shape in cross-section, dark reddish brown bark, smooth texture of bark, medium to thick, medium to many lenticels

PETIOLE: present
LEAF: simple type, alternate arrangement along shoot
LEAF BLADE: ovate shape, acute apex, cuneate to obtuse base, absent or very weak rugosity when newly open, medium to strong rugosity when aged
LEAF BLADE MARGIN: serrate type distributed along entire margin, absent or very weak undulation, sparse pubescence
LEAF BLADE (UPPER SIDE): brown red (close to RHS 180B) when newly open, medium brown (close to RHS 176A) when young, brown green (greener than RHS N138B) with greyed green appearance when fully open, absent or very sparse pubescence
LEAF BLADE (LOWER SIDE): light green, absent or very sparse pubescence between veins, sparse pubescence along veins, weak glaucosity between veins, absent or very weak glaucosity of veins

FLOWERING: begins early after leaf emergence, short period
INFLORESCENCE: compound corymb type, medium number of flowers
PEDUNCLE: foliage present
PETAL: white (RHS NN155D) inner side
STAMEN: longer than petal, white anther

Origin & Breeding History: 'SMSMBK' was bred and developed by the breeder, Timothy D. Wood, an employee of Spring Meadow Nursery, Inc. in Grand Haven, Michigan, USA. It originated from an open pollinated cross that occurred during the summer of 2007 in Grand Haven, Michigan, between Spirea japonica variety 'SSBLUE, as the female parent, and an unknown male parent. From the resulting progeny, 'SMSMBK' was selected during the summer of 2009 for its compact plant growth habit, good mildew resistance, large white inflorescences, and blue foliage with red new growth. 'SMSMBK' was first reproduced asexually by softwood cuttings during the summer of 2009 in Grand Haven, Michigan, USA.

Tests & Trials: The comparative trial for 'SMSMBK' was conducted as an outdoor container trial during the spring and summer of 2017 at BioFlora Inc. in St. Thomas, Ontario. The trial included 10 shrubs of the candidate variety and 5 shrubs of the reference variety. The shrubs originated from 10 cm long rooted cuttings that were transplanted into 8.8 litre pots on July 16, 2016. The shrubs were overwintered in a non-heated double polyhouse. The observations and measurements were taken from 10 shrubs or parts of 10 shrubs of the candidate variety and 5 shrubs or 10 parts of 5 shrubs of the reference variety on July 6, 2017, with the exception of the flower characteristics which were observed on June 3, 2017. All colour determinations were made using the 2007 Royal Horticulture Society (RHS) Colour Chart.

Comparison tables for 'SMSMBK' with reference variety 'Snow Storm'

Plant height (cm)

Plant width (cm)

Leaf blade length (cm)

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Spirea: 'SMSMBK' (left) with reference variety 'Snow Storm' (right)

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Spirea: 'SMSMBK' (left) with reference variety 'Snow Storm' (right)

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Spirea: 'SMSMBK'