Bignoniaceae

 

This large Family of more than a hundred genera (and about 700 species) is chiefly found in tropical and sub-tropical regions around the world – the centre of diversity (with the highest density of species) is in South America.

 

The Family contains trees, shrubs and herbaceous plants but is predominantly (about half the species) made up of climbers (lianas, vines).

 

The flowers are generally large, showy and colourful and are hermaphrodite. The fruit is usually a capsule in the form of an elongated pod - which dehisces longitudinally to release the seeds. The pods contain numerous seeds and these are normally winged.

 

The seeds germinate without pretreatment – however, in those cases where the seeds appear to have a hardish seed coat, it would be prudent to give them a warm water soak before sowing to facilitate imbibition. Germination will then be most efficient and productive at relatively high temperatures (25˚+C).

 

The following genera of climbers are suitable for mild niches in the UK – Bignonia, Campsis, Doxantha, Eccremocarpos, Pandorea; while Clytostoma, Distictis, Podranea, Pyrostegia, Tecoma and Tecomaria are more suited to Mediterranean climate areas or, in the UK, in very mild niches or in a frost free conservatory.

 

The ‘Indian Bean Tree’ (Catalpa) is certainly hardy in most of Southern Britain and is regularly encountered in supermarket car parks where it seems to flourish and fruit! In warm, arid areas the ‘Desert Willow’ (Chilopsis linearis) is a useful small tree and has a range of flower colours.