Berberis ottawensis ‘Superba’ (= B. thunbergii atropurpurea superba)
Habit: Normal to large shrub, 3-4 m tall, up to 2 (3) m wide; shoots with strong thorns, arching, lilting to the ground; fast-growing.
Flowers: Conspicuous and plentiful; densely packed, saturated yellow panicles, May; strong, pungent smell.
Fruits: Light red berries, persistent into winter, very sour but edible.
Leaves: Strong brown-red or even black-red with a metallic shimmer, in autumn a colourful display ranging from flame-orange to dark red.
Demands: Sun; loses its typical leaf colour in shade; frost hardy; tolerates urban and industrial pollution.
Soil: Any garden soil, fresh to dry.
Note: Very old specimens have a mixed grey-brown colour; cut back every few years to give them a more intense black-red colour.
Hardiness: Zone 6