SB300

Boxwood

Variety Description

Varieties used for comparison: 'Winter Gem' and 'Jim Stauffer'

Summary: The plants of ‘SB300' have an upright growth habit while those of ‘Jim Stauffer' have a bushy rounded growth habit. The stem shoot of ‘SB300' is narrower than that of the reference varieties. The stem shoot of ‘SB300' is longer than that of the reference varieties. In the summer, the plants of ‘SB300' are shorter than those of ‘Winter Gem' and taller than those of ‘Jim Stauffer'. The plants of ‘SB300' are narrower than those of the reference varieties. The plants of ‘SB300' have dense foliage whereas the plants of the reference varieties have medium density foliage. The leaf blade of ‘SB300' is wider than that of the reference varieties.

Description:

SHRUB: evergreen type, upright growth habit, compact shape, many branches, dense foliage

STEM: absent or very weak intensity of anthocyanin colouration, edged shape, light brown, no twisting

PETIOLE: present
LEAF: opposite arrangement, simple type
YOUNG LEAF BLADE: medium green (RHS 144A) on upper side
LEAF BLADE: elliptic to broad elliptic shape, retuse shape of apex, cuneate shape of base, entire margin, no variegation, medium contrast between new and mature growth
LEAF BLADE (UPPER SIDE): medium glossiness, absent or very sparse pubescence, dark green to dark brown green (RHS 137B-A) mature growth, grey brown (closest to but greener than RHS N199D) winter foliage
LEAF BLADE (LOWER SIDE): absent or very sparse pubescence, light green, dark green brown (closest to RHS 152C-D) winter foliage

Origin & Breeding History: 'SB300' was discovered in the summer of 2007, as a presumed branch mutation off of 'Wintergreen' in Piney River, Virginia. After further evaluation, 'SB300' was selected as a unique plant in 2008. The selection criteria included growth and leaf characteristics.

Tests & Trials: The comparative trial of 'SB300' was conducted as an outdoor container trial during the summer of 2024 at BioFlora Inc. in St. Thomas, Ontario. The trial included a total of 10 shrubs of the candidate variety and 10 shrubs of the reference varieties. All shrubs were grown from 5.5 cm liners that were each planted into a 4 litre container in August 2023. Observations and measurements were taken from 10 plants or parts of plants of the candidate and reference varieties on June 14, 2024. The flowering characteristics were not assessed. All colour determinations were made using the 2015 Royal Horticultural Society (RHS) Colour Chart.

Comparison tables for 'SB300' with reference varieties 'Winter Gem' and 'Jim Stauffer'

Stem shoot thickness (cm)

Stem shoot length (cm)

Plant height in summer (cm)

Plant width in summer (cm)

Leaf blade width (cm)

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Boxwood: ‘SB300' (left) with reference varieties ‘Winter Gem' (centre) and ‘Jim Stauffer' (right)

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Boxwood: ‘SB300' (left) with reference variety ‘Winter Gem' (right)