Berberis aggregata aka Clustered Barberry

Berberis aggregata is a deciduous shrub in the barberry family, Berberidaceae. Common names include clustered barberry and salmon barberry. Its native range runs from eastern Qinghai to central China. Plants For A Future also records it in western China. There, it grows in thickets and beside streams. These habitats reach about 8,200 feet [2,500 metres] above sea level.

This compact, bushy shrub loses its leaves for winter. Garden plants reach 3.3–4.9 feet [1–1.5 metres] tall. Their spread reaches 4.9–8.2 feet [1.5–2.5 metres]. They take five to ten years to reach full size. The leaves have an olive-green upper face and blue-green undersides. Small teeth line their edges. Leaves reach about 0.1 feet [0.03 metres] long. They turn red in autumn, adding a second season of colour.

Small, pale yellow flowers appear in late spring and early summer. They form tight panicles along the shrub. Each panicle reaches about 0.13 feet [0.04 metres] long. Round red fruit follows in autumn, with a grey tinge. Each fruit measures about 0.023 feet [0.007 metres] across. Plants For A Future describes heavy, reliable fruit crops along the stems. The autumn leaves and fruit give this shrub much of its garden value.

Grow it in sun or part shade with good drainage. Full sun gives the best flower and fruit display. It accepts clay, chalk, loam, and sandy soils. Acid, neutral, and alkaline soils all suit it. The RHS lists both moist, well-drained soil and well-drained soil. It also accepts exposed or sheltered sites. The RHS rates its hardiness H7, covering cold below −20°C. Plants For A Future lists USDA zones 5–9. Suitable settings include coastal, courtyard, cottage, and wildlife gardens. It also suits borders, hedges, and screens.

Trim hedges once flowering ends. Sow seed in early spring, or take semi-ripe cuttings in summer. Aphids and berberis sawfly may attack this shrub. Powdery mildew and honey fungus can also cause problems. Sources disagree about eating the fruit. Plants For A Future describes it as edible, raw or cooked. It reports a sharp taste with a lemon-like flavour. The RHS warns people and pets not to eat the fruit. It also advises gloves and protective gear when handling plants. Given this conflict, do not treat the fruit as established safe food.