Family: Papilionaceae
Common Name: Indigo

Found in tropical and subtropical regions throughout the world, this large genus of around 700 species includes annuals and perennials, as well as evergreen and deciduous shrubs and small trees. Many of the species cultivated are shrubs with dark, blueish green foliage and sprays of pea-like flowers which make an attractive display during spring. The colours of the flowers range from purple to pinkish lilac. I. tinctoria is the source of the dark blue dye, known as indigo, highly valued in times past.

Species

I. amblyantha, zone 5, from Asia, is a shrub, to 2 m (6 ft), with pink flowers.

I. australis, Australian indigo, zone 9, is one of the more tender species. It grows to about 1.5 m (4 ft) tall with bluish green, pinnate leaves and sprays of pink, purple or, very occasionally, white flowers.

I. decora, zone 5, from China and japan, is a small shrub, to 60 cm (24 in), with reddish new growth, light green, pinnate leaves and abundant sprays of pinkish white blooms during the warmer months of the year. It tends to spread by underground runners but these can be easily pulled out when young.

I. heterantha, zone 7, a hardy, 2-3 m (6-10 ft) high shrub with a spreading habit, flowers profusely with lovely, rose-coloured blooms.

Cultivation

Indigoferas will grow in most garden soils, provided they are moist and well drained. The plants will flower more freely if regularly watered. Propagate from seed, which germinates more quickly if soaked overnight in warm water before sowing, as the seed coat is hard and waxy. They can also be propagated from cuttings and often from suckers.

Climate

There are species suited to various climates.