Indigofera heterantha or Himalayan Indigo was also known as Indigofera gerardiana previously. It is part of the Fabaceae family of plants. Indigofera heterantha is a hardy herbaceous shrub. It is native to the Northwest Himalaya of Tibet.
Indigofera heterantha has gray-green pinnate leaves. Flowers are purplish-pink, pea-like, and appear in racemes in early summer, (June to September).
I came across the ones in these photos in the garden of St. John’s Chruch, Waterloo. Plant it in full sun, in well-drained soil. It is pest-free and disease-free. Propagate by seed or semi-hardwood cuttings. Indigofera heterantha grows from 1.5 to 2.5m or 5 to 8ft. Hard prune old wood in spring. It attracts bees. The plant is drought-tolerant.