Himalayan indigo Indigofera heterantha
Himalayan indigo (Indigofera heterantha) is a deciduous perennial shrub in the Fabaceae family, native to Western Himalaya (Afghanistan, Pakistan, Kashmir to Nepal). It grows 1.5–3 m (4.9–10 ft) tall and 1.5–3 m (4.9–10 ft) wide, wants full sun and low water, and is hardy to about -20 °C (-4 °F). Space plants about 2 m (6.6 ft) apart.
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Himalayan indigo at a glance
| Type | Perennial shrub, deciduous |
|---|---|
| Family | Fabaceae |
| Mature height | 1.5–3 m (4.9–10 ft) |
| Mature spread | 1.5–3 m (4.9–10 ft) |
| Spacing | 2 m (6.6 ft) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 5.5–8 |
| Cold hardiness | About -20 °C (-4 °F) once established (roughly USDA zone 6) |
| Heat stress | Likely above about 34 °C (93 °F) |
| Flowering | from about June for 9–14 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Western Himalaya (Afghanistan, Pakistan, Kashmir to Nepal) |
| Common in gardens of | 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇺🇸 United States, 🇩🇪 Germany, 🇳🇱 Netherlands, 🇮🇳 India |
Is Himalayan indigo toxic?
- People: not well documented
- Cats: not well documented
- Dogs: not well documented
No reports of poisoning; some Indigofera species are toxic to livestock, so do not let animals browse it heavily.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Himalayan indigo
Good neighbours
- good With Sweet corn: "Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils. Evidence C
Keep apart or take care
- caution With Alliums (onion family): Onions, garlic and leeks are said to stunt beans and peas (allium root exudates may reduce nodulation). Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
- caution With Alliums (onion family): Beans and peas are traditionally kept away from onions, garlic and leeks. Traditional companion-planting advice; controlled trials are few, so treat it as a soft preference. Evidence D
- caution With Fennel: Fennel is reported to suppress beans and peas growing next to it. Evidence C
Questions about Himalayan indigo
- How far apart should I plant Himalayan indigo?
- About 2 m (6.6 ft) apart, centre to centre. A mature plant spreads 1.5–3 m (4.9–10 ft).
- Does Himalayan indigo need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Himalayan indigo need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Himalayan indigo?
- It tolerates about -20 °C (-4 °F) once established, roughly USDA zone 6.
- When does Himalayan indigo flower?
- From about June for 9–14 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Himalayan indigo poisonous to cats and dogs?
- For cats it is not well documented; for dogs not well documented; for people not well documented. No reports of poisoning; some Indigofera species are toxic to livestock, so do not let animals browse it heavily.
- What grows well with Himalayan indigo?
- "Three sisters": climbing beans use corn as a support and fix nitrogen; the benefit to the corn is modest but real in low-input soils.
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Flora of Nepal (online flora and checklist), Royal Botanic Garden Edinburgh with Nepalese and international partners
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- A late-leafing, airy shrub with grey-green pinnate leaves and spikes of rosy-purple pea flowers from midsummer into autumn; loved by bees. In cold gardens it may die back to the base and regrow like a perennial.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Bush bean Phaseolus vulgaris
- Garden pea Pisum sativum
- Sweet pea Lathyrus odoratus
- Runner bean Phaseolus coccineus
- Broad bean (fava) Vicia faba
- Lima bean Phaseolus lunatus
- Cowpea (black-eyed pea) Vigna unguiculata
- Yardlong bean Vigna unguiculata subsp. sesquipedalis