Commonly known as ‘Bladder Senna’
This is another of those plants which enjoy growing in dry coastal situations where they self seed themselves copiously without much difficulty. They also grow well in a hot sunny shrub border or a dry sunny bank. In recent years they have become a common sight in urban gardens and public places where they seem to tolerate urban pollution with no ill effect.
Colutea are bushy shrubs growing to 8 or 10ft in milder locations. If they are cut back in a cold winter they will quickly regenerate from the base. The thing they all have in common which makes them easy to identify is their unusual inflated bladder-like seed pods. These ‘bladders’ are a feature which this genus shares only with staphylea and koelreuteria. If you squeeze a half ripe bladder it will burst with a loud ‘pop’. When fully ripe the bladders turn from green to translucent white and will eventually ‘pop’ on their own to scatter the seeds widely over the surrounding area.
C. arborescens has pinnate pale green leaves similar, perhaps, to those of coronilla. These are up to 6in long with five or six pairs of ovate leaflets. The pea like yellow flowers appear in racemes of three to eight individual flowers and the racemes can be 4-5in long. They appear in June and July.
C. x media ‘Copper Beauty’ has similar shaped flowers in slightly smaller racemes. The flowers are a coppery red with yellow markings and the seed pods are around 2in long and, again, slightly smaller than in C. arborescens but otherwise identical.
Colutea are easy to grow and even easier to collect seed from the bladders. These can be sown in the cold frame in autumn or in containers in the greenhouse in the spring. So easy are they that it is hardly worth the effort of growing these plants from cuttings!
