Family: Poaceae

Origin, Description & Uses
Sorghum bicolor nothosubsp. drummondii, commonly known as shattercane, is a weedy relative of cultivated sorghum that originated through hybridization involving domesticated sorghum and its wild relatives in Africa. It is an annual grass that can grow over 10 feet (3 m) tall, with broad leaves, stout stems, and large seed heads that resemble cultivated grain sorghum. Shattercane has been used as a forage plant for livestock and occasionally occurs as a volunteer crop in agricultural areas. However, it is more commonly recognized as an agricultural weed that readily colonizes disturbed sites, roadsides, pastures, and fallow fields.

Risks & Threats
Shattercane is naturalized in the Hawaiian Islands and possesses traits that are cause for concern in tropical island ecosystems. It grows rapidly, produces abundant seed, and readily spreads into disturbed habitats, agricultural lands, roadsides, and open natural areas. The species can form dense stands that compete with desirable vegetation, reduce crop productivity, and create persistent seed banks that are difficult to manage. Its ability to hybridize with cultivated sorghum can also complicate agricultural weed control efforts. Because of its invasive characteristics and potential to negatively impact both agricultural and natural ecosystems, Plant Pono recommends choosing a low-risk or native alternative whenever suitable alternatives are available.

High Risk Traits:

• Naturalized on O'ahu, Lāna'i, and Hawai'i
  
• Severe agricultural weed (corn/soybean/sorghum yield losses up to 97%)
  
• Congeneric weed (johnsongrass is noxious)
  
• Naturalized outside native range
  
• Toxic to livestock (cyanide, nitrates)
  
• Host to crop pests/pathogens
  
• Prolific seed production (~2,000/plant)
  
• Persistent seed bank (up to 13 years)
  
• Hybridizes with crops and wild relatives
  
• Self-compatible
  
• Dispersed by cultivation, seed contamination, water, and animal gut
  
• Tolerates grazing/mowing

Low Risk Traits:

• No spines, burrs, or thorns
  
• Non-climbing, erect growth
  
• No vegetative reproduction (annual, no rhizomes)
  
• Shade-intolerant