By the time August arrives, there are not so many shrubs in flower as earlier in the season. Long gone are the heady days of spring with magnolias, berberis and weigelas, the shrub roses have finished their luscious display, and the hydrangeas are beginning to look a little weary. So anything light and airy and floating above the melee of the summer border is to be welcomed.
Indigofera heterantha, formerly sold under the name I. gerardiana, is a member of the pea family, native to the northwestern Himalayas. It has pinnate leaves, grey-green in colour, and “rose-purple” pea-like flowers. Disease- and pest-free, it is also resistant to honey fungus
It likes a hot and sunny position in moist, fertile, well drained soil, although it will put up with clay as long as it does not become waterlogged in the winter. Although hardy in most parts of the UK, taking temperatures as low as -15C, top growth may be killed to the ground in cold areas, but the shrub readily regenerates from the roots. An established shrub will make up to ten feet of growth in a season. For many years, I cut it back to a three feet stump, but found the new growth becoming increasingly unwieldy as the season progressed, and now treat it like a perennial, cutting it back to ground level in early spring. There then comes an anxious wait as this is a late starter, waiting to May to start into growth again