How to Prune Bean's broom?
Shorten flowered shoots to vigorous sideshoots; remove about a third of stems at ground level annually. Prune immediately after flowering.

Bean's broom · Cytisus × beanii
Plant young plants in full sun in well-drained soil; grows better in poor soils rather than rich soils
Shorten flowered shoots to vigorous sideshoots; remove about a third of stems at ground level annually. Prune immediately after flowering.