NCBT1

Japanese Barberry

Variety Description

Variety used for comparison: 'Atropurpurea Nana' (Crimson Pygmy)

Summary: The plants of 'NCBT1' are larger than those of 'Atropurpurea Nana'. The young shoot of 'NCBT1' is dark brown purple with dark brown purple leaves while that of 'Atropurpurea Nana' is dark purple red to dark red with dark red leaves. The leaf of 'NCBT1' is wider than that of 'Atropurpurea Nana'. The leaf of 'NCBT1' is circular to obovate while that of 'Atropurpurea Nana' is broad elliptic. The upper side of the leaf of 'NCBT1' is black while that of 'Atropurpurea Nana' is dark brown.

Description:

PLANT: deciduous, compact rounded and spreading growth habit, very dense foliage, broader than tall

BRANCH: semi-erect to horizontal attitude
YOUNG SHOOT: dark brown purple (RHS 183B), leaf dark brown purple (RHS 178A)
STEM: simple spines, ranging between one to three and four to six leaves per node

LEAF: circular to obovate, spines only on apex, obtuse apex, black (RHS N186A) on upper side, no secondary colour, absent or weak glossiness, flat profile in cross-section, absent or very weak undulation of margin

FLOWER: single or raceme type
FLOWER BUD: red
PETAL: medium yellow (RHS 12A), rounded apex

FRUIT: absent

Origin & Breeding History: 'NCBT1' originated from an induced mutation of the parent plant Berberis thunbergii var. atropurpurea conducted in the spring of 2005 in Mills River, North Carolina, USA. The mutation was induced by treating seed of Berberis thunbergii var. atropurpurea with the mutagen ethyl methanesulfonate. The new barberry variety 'NCBT1' was selected in the summer of 2006 based on its compact plant growth habit, purple foliage colour and very low flower fertility. Asexual reproduction of 'NCBT1' was first conducted by stem cuttings in 2007 in Mills River, North Carolina, USA.

Tests & Trials: The comparative trial for 'NCBT1' was conducted in a greenhouse at Spring Meadow Nursery in Grand Haven, Michigan, USA from 2022 to 2023. The trial included a total of 10 plants each of the candidate and reference variety. All plants were grown from rooted cuttings and transplanted in 11 litre pots in 2022. Observations and measurements were taken from 10 plants, or parts of plants, of each variety on July 31, 2023. All colour determinations were made using the 2015 Royal Horticultural Society (RHS) Colour Chart. Mean differences were significant at the 5% confidence probability level based on a paired Student's t-test.

Comparison tables for 'NCBT1' with reference variety 'Atropurpurea Nana'

Plant height (cm)

Plant width (cm)

Colour of young shoot (RHS)

Leaf blade width (cm)

Colour of leaf blade (RHS)

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Japanese Barberry: 'NCBT1' (left) with reference variety 'Atropurpurea Nana' (right)

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Japanese Barberry: 'NCBT1' (left) with reference variety 'Atropurpurea Nana' (right)