Colutea arborescens

Bladder senna. A medium or large deciduous shrub from the Mediterranean region, growing up to 5 m (16 ft) high; naturalised in Britain. A nitrogen-fixing legume. A good hedging and bee plant; the leaves have been used medicinally, and the wood is used for implements, small furniture items and makes good fuel. Likes full sun and a well-drained soil; hardy to -20°C.