Colutea Arborescens or Bladder Senna
The generic name is derived from the Greek word koiloun, meaning hollow, which refers to the hollow, bladder-like form of the seed pods. The genus includes some 20 species distributed from southern Europe to the Himalayas. They are deciduous, sometimes thorny shrubs with odd-pinnate leaves and small stipules. The pea-likeare typical of the family.
Bladder senna is a 4 m (13 ft) high shrub. The leaves are composed of nine to thirteen oval leaflets, 15 to 20 mm (½ to ¾ in) long, bright green above, a paler green below and slightly hairy. The flowers, about 2 cm (¾ in) across, are yellow with reddish markings on the keel and are arranged in racemes of six to eight flowers on long stalks. The pods are bladder-like, inflated, smooth, green, and slightly reddish at the base. Bladder senna is a native of southern Europe and North Africa. It flowers in May and June.
It is readily propagated by means of seeds, which are sown in November, and may also be increased by summer cuttings. It has no specialrequirements and will grow even in dry and stony soils, but it needs a sunny situation. It can be planted as a solitary specimen, in groups, or in rows to form untrimmed hedges.