How to Fertilize Spanish broom?
Balanced perennial feed every four weeks spring through summer growth

Spanish broom · Spartium junceum
Also known as: rush broom; weaver's broom
Thrives on poor, well-drained soils in exposed, sunny sites and can become leggy in sheltered positions. Good for coastal situations and chalk but is not fully hardy in the UK
Balanced perennial feed every four weeks spring through summer growth