Crotalaria lanceolataE.Mey.

lanceleaf rattlebox

WFO wfo-0000209445 Accepted WFO 2026-06 8 photographs CC BY / CC BY-SA

Plate 1 figs. a–h · 8 separate observations

Crotalaria lanceolata, photographed by Greg Tasney
fig. a Greg Tasney, CC BY-SA 4.0 / 2022-05-08 / obs. 195879834

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

Native range 14 botanical countries

Regions where Crotalaria lanceolata is native: Cape Provinces, Eswatini, Ethiopia, Kenya, KwaZulu-Natal, Madagascar, Malawi, Mozambique, Northern Provinces, Sudan-South Sudan, Tanzania, Uganda, Zambia, Zimbabwe Cape ProvincesEswatiniEthiopiaKenyaKwaZulu-NatalMadagascarMalawiMozambiqueNorthern ProvincesSudan-South SudanTanzaniaUgandaZambiaZimbabwe
Native distribution of Crotalaria lanceolata, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.
RegionTDWG codeContinent
Cape Provinces CPP AFRICA
Eswatini SWZ
Ethiopia ETH
Kenya KEN
KwaZulu-Natal NAT
Madagascar MDG
Malawi MLW
Mozambique MOZ
Northern Provinces TVL
Sudan-South Sudan SUD
Tanzania TAN
Uganda UGA
Zambia ZAM
Zimbabwe ZIM

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Flowering 81 in flower of 97 examined

Proportion of examined Crotalaria lanceolata in flower, by month
Month In flower Examined Share 95% interval
Jan 6 7 86% 49% to 97%
Feb 12 14 86% 60% to 96%
Mar 11 12 92% 65% to 99%
Apr 9 9 100% 70% to 100%
May 3 4 too few examined
Jun 4 4 too few examined
Jul 4 5 80% 38% to 96%
Aug 9 9 100% 70% to 100%
Sep 8 9 89% 56% to 98%
Oct 6 11 55% 28% to 79%
Nov 5 9 56% 27% to 81%
Dec 4 4 too few examined

Peak flowering in Apr. Each bar is the share of Crotalaria lanceolata observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 81 of 97 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 3 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Where it actually grows measured, from 679 observations

Condition 5th percentile Median 95th percentile
Coldest month, mean daily low 6.5 °C 10.7 °C 16.6 °C
Warmest month, mean daily high 25.1 °C 29.9 °C 32.1 °C
Annual rainfall 885 mm 1,352 mm 1,845 mm
Rainfall in the driest quarter 90 mm 186 mm 346 mm

It is barely found anywhere that freezes. This is not care advice and it is not a forecast. It is a measurement: we sampled the climate at every one of the 679 research-grade observations of Crotalaria lanceolata that carry a coordinate, and this is the range those places actually span. The 5th and 95th percentiles are used rather than the minimum and maximum, because a single cultivated specimen in a heated conservatory should not widen a tropical plant's range to the Arctic.

This is not a hardiness zone. A USDA zone is the average annual extreme minimum temperature. The figure above is the mean daily minimum of the coldest month, which is a different quantity and is typically far warmer. Reading one as the other would place a plant several zones too warm, so we do not publish a hardiness zone, because we do not have one. Climate from CHELSA V2.1 (Karger et al. 2017); occurrences from 10.15468/dl.cgje2x.

Also published as 1 synonym

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

  • Crotalaria mossambicensis Klotzsch

Sourcesevery claim on this page

  1. World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
  2. iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
  3. Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. Retrieved 2026-07-13.
  4. Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.