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Invasive Species: African Oxygen Weed

African Oxygen Weed

(Lagarosiphon major)
*Not established in Michigan*


Report this species:

Use the Midwest Invasive Species Information Network (MISIN) online reporting tool 

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  • Submerged aquatic plant.
  • Dark green, alternating leaves curl downward.
  • Form dense mats up to 3 feet thick.
  • Stems grow up to 20 feet long with ‘j’ shaped curve.

african oxygen weed
Photo courtesy of Rohan Wells, NIWA,

african oxygen weed
Photo courtesy of Robert Videki, Doronicum Kft.,

Habitat: African oxygen weed inhabits freshwater lakes and slow flowing rivers. Cool water and abundant light are preferred.

Native Range: South Africa.

Local Concern: Dense mats of African oxygen weed impede other aquatic organisms by decreasing oxygen levels, increasing pH levels, decreasing sunlight penetration, increasing decomposition of dead plants and reducing biodiversity. Recreation is also extremely limited in infested areas.

Potential Means of Introduction: Escape from aquarium and water garden industry, spread by water current or boats.


African Oxygen Weed Invasive Species Alert - Printable PDF

MDARD Weed Risk Assessment for African Oxygen Weed (Lagarosiphon major) -  Printable PDFThis document evaluates the invasive potential of the plant species using information based on establishment, spread and potential to cause harm.