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Fabaceae family

Blue Rattlesnake Crotalaria verrucosa

Blue Rattlesnake is an introduced annual shrub, found in Hawaii, the lower 48 states, and U.S. outlying islands.

More about this plant

Crotalaria verrucosa, the blue rattlepod, is a species of flowering plant in the legume family, Fabaceae. This shrub belongs to the subfamily Faboideae. The herb can be found in tropical and subtropical areas from in Bangladesh to Sri Lanka in South Asia, Southeast Asia, Australasia and Central America. Wikipedia →

⚠ Invasive here — plant a native instead USDA + GBIF

Blue Rattlesnake is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.

Yellow Nicker
Native
Yellow Nicker
Caesalpinia bonduc
●●●●○
Salt Heliotrope
Native
Salt Heliotrope
Heliotropium curassavicum
●●●●○
Salt Heliotrope (var. curassavicum)
Native
Salt Heliotrope (var. curassavicum)
Heliotropium curassavicum var. curassavicum
●●●●○
Sweet Acacia
Native
Sweet Acacia
Vachellia farnesiana
●●●●○
Matched on growth habit · bloom months · mature height · shared U.S. range (USDA + GBIF) — a starting point, not a prescription.

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 11 derived from its U.S. range
Size & form
Sources · Size & form
USDA PLANTS — Lifespan
TRY Plant Trait Database (CC BY 4.0) — Foliage
Lifespan
Annual
Foliage
Broadleaf
In the garden
Shrub layer — Sits in the shrub of a layered food forest or polyculture.Open guide →
Nitrogen fixer — Fixes atmospheric nitrogen through root-nodule bacteria — builds soil fertility for itself and its neighbours, cutting fertiliser need.Open guide →
derived roles
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

Wildlife & pollinators

How pollinator value is scored →
❧ Caterpillar hosts ~6 caterpillar species

Crotalaria supports ~6 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.

Recorded feeding on Crotalaria in North America, including:

Erynnis baptisiae · Wild Indigo Duskywing Etiella zinckenella · snout moth Helicoverpa zea · Corn Earworm Hemiargus ceraunus · Ceraunus Blue Incisalia irus · gossamer-winged butterfly Phoebis sennae · Cloudless Sulphur
+ 4 more species →
Pima granitella · snout moth Syncopacma crotalariella · twirler moth Utetheisa bella · tiger moth Utetheisa ornatrix · Ornate Bella Moth
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
✦ Bees 1 bee visitor

1 native & managed bee species is documented visiting Blue Rattlesnake :

Xylocopa mordax · carpenter bee
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
How we know this (1) Methods & honest limits
Photosynthesis Direct fact

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.

Kattge, J. et al. TRY plant trait database — Categorical Traits Dataset (2012).
Derived values are computed from open data by a published method — labelled, cited, and never shown as a direct observation. Full methodology →
Sources for this entry (22) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — US-RIIS v2.0 (USGS)
[07] Description — Wikipedia (CC BY-SA)
[08] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[09] Conservation rank — NatureServe Explorer (CC BY)
[11] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[12] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[13] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[14] Nitrogen fixation — Werner et al. 2014 (Dryad, CC0)
[19] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[20] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[21] Caterpillar species — NHM HOSTS (CC0)
[22] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
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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