Hairy Indigo Indigofera hirsuta
Hairy Indigo is an introduced annual shrub, found in the lower 48 states and Puerto Rico. It grows to 5 ft and blooms Aug in part shade – shade, with brown fruit.
More about this plant
Indigofera hirsuta, the hairy indigo or rough hairy indigo, is a species of flowering plant in the family Fabaceae. It is native to nearly all the world's tropics; South America, Africa, Madagascar, the Indian Subcontinent, southern China, southeast Asia, Malesia, Papuasia and Australia, and has been introduced to the Caribbean, the southeast United States, Mexico and Central America. It is used as a green manure and, to a minor extent, for forage. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Part shade – shade
- Soil & moisture
- Medium moisture
- Soil pH
- 5–8
- Fertility need
- Low
- Adapts to
- Medium (loam), Fine (clay)
- Hardiness
- USDA zone 9+
- Height
- 5 ft
- Spread
- None — clumping
- Growth rate
- Moderate
- Growth form
- Bunch
- Lifespan
- Annual
- Foliage
- Evergreen broadleaf · fine texture
- Active growth
- Spring & summer
- Fruit
- Brown persists into winter
- Flower colour
- Red AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
- Propagate by
- Seed
- Seed starting
- No stratification needed
- Seeds ripen
- Autumn – Winter seed-collection / harvest window
- In the trade
- No known commercial source
- Deer browsing
- Low often deer-resistant
- Resprouts if cut
- No
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~4 caterpillar species
Indigofera supports ~4 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a modest genus for introduced plants — native genera typically support far more.
Recorded feeding on Indigofera in North America, including:
+ 2 more species → ↑ show fewer
Wildlife & visitors 2 nectaring
Open records of who else uses Hairy Indigo — a generalist food-web signal, kept separate from the keystone Ecological Value.
2 adult butterfly & moth species are recorded nectaring at its flowers:
Related plants
More Indigofera →
How we know this (3) Methods & honest limits
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (34) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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