Khaki weed

Alternanthera pungens

Introduction:

Alternanthera pungens, commonly known as Khaki Weed, is a herbaceous perennial plant belonging to the Amaranthaceae family. Native to South America, it has become invasive in various regions, particularly in Australia, where it is considered a noxious weed. Khaki Weed is known for its rapid growth, ability to form dense mats, and its spiny seed heads, which can be a nuisance in lawns and pastures.

Identification:

Appearance: Khaki Weed is a low-growing, spreading plant with a prostrate or decumbent habit. The leaves are lance-shaped, opposite, and often have a reddish tint. The most distinctive feature is the seed head, which consists of spiky burrs containing seeds. The burrs can easily attach to clothing, fur, and human skin.

Distinctive Features:

  1. Habit: Low-growing and spreading, forming dense mats.
  2. Leaves: Lance-shaped, opposite, with a reddish tint.
  3. Seed Heads: Spiky burrs containing seeds, which can cling to clothing and fur.

Habitat and Distribution:

Khaki Weed is commonly found in disturbed areas, lawns, pastures, and along roadsides. It prefers well-drained soils and is highly adaptable to various environments. Its invasive nature has led to its spread in regions outside its native range.

Impact and Management:

  1. Invasive Potential: Khaki Weed can quickly form dense mats, outcompeting desirable vegetation in lawns and pastures.

  2. Spreading Mechanism: The spiky seed heads easily attach to animals and clothing, aiding in the plant's spread.

  3. Management Strategies:

    • Mechanical Control: Regular mowing or cutting before seed production can help reduce the spread of Khaki Weed. It is important to prevent the formation and dispersal of spiny seed heads.
    • Chemical Control: Selective herbicides targeting broadleaf weeds can be applied, especially during the plant's active growth phase. Consult with local agricultural extension services for appropriate herbicide recommendations and application methods.
    • Cultural Practices: Maintaining a healthy and competitive stand of desirable vegetation through proper lawn care practices can help suppress the growth of Khaki Weed.

Caution: The spiky burrs of Alternanthera pungens can be a nuisance, causing discomfort to animals and attaching to clothing and skin. Care should be taken when handling infested material.