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Sunn Hemp

Crotalaria ochroleuca


Crotalaria ochroleuca is an annual herbaceous plant utilized for fiber, forage, and as a green manure cover crop. Reaching heights of 2.5 m, C. ochroleuca bears long, slender, trifoliate leaves and five-petalous blooms (banner, wing, and keel) similar to other legumes.


C. ochroleuca  is most often used for forage and as a green manure cover crop. Grown in rotation with commodity crops, C. ochroleuca builds soil nutrition between crops. As a forage crop, young, tender C. ochroleuca leaves and stems can supplement animal feeds up to 10% (particular care should be taken to limit ingestion of flowers and seeds as these contain much higher amounts of the antinutritive alkaloid also found in C. juncea).


  • Elevation – up to 2000 m
  • Rainfall – found in floodplains, swamps, and along rivers, though when established also tolerates very dry conditions
  • Soil Types – unclear
  • Temperature Range – unclear; intolerant of frost
  • Day Length Sensitivity – short-day sensitive
  • Light – prefers full sun

C. ochroleuca seed should be planted 2-3 cm deep (preferred, if possible), or broadcast, at a rate up to 25 kg/ha, depending on use. Germination and establishment success can be dependent on moisture conditions and sun exposure (full sun preferred). C. ochroleuca does tolerate water-saturated soils much more than its cousin, C. juncea. Upon establishment, C. ochroleuca requires relatively little management.

Harvesting and Seed Production

If utilizing as forage, C. ochroleuca should be harvested 6-8 weeks after planting. For green manure cover crop use, it is recommended to cut C. ochroleuca 10-12 weeks after planting, before full bloom of the stand and before plants become too fibrous to incorporate.   

Pests and Diseases

Can be affected by powery mildew and Fusarium wilt under humid conditions. C. ochroleuca has demonstrated ability to suppress some pestilent nematodes.

Cooking and Nutrition

Due to antinutritive properties, C. ochroleuca is not for human consumption.


Crotalaria ochroleuca G. Don, Taxonomic Serial No.: 501807.” ITIS Standard Report Page: Crotalaria ochroleuca, www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=501807#null.

Mkiwa, F.E., Lwoga, A.B., Mosha, R.D., and Matovelo, J.A. 1994. Antinutritional effects of Crotalaria ochroleuca (marejea) in animal feed supplements. Vet Hum Toxicol 36(2):96-100.

Common Names

  • French
    • sonnette
  • Swahili
    • marajea

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