Common knotgrass

Polygonum aviculare

Introduction: Polygonum aviculare, commonly known as common knotweed or prostrate knotweed, is an annual herbaceous plant belonging to the Polygonaceae family. Native to Eurasia, it has become naturalized in many parts of the world. Recognized for its prostrate growth habit and adaptability to a variety of environments, common knotweed is often found in disturbed areas and open spaces.

Identification:

1. Morphology:

  • Height: Common knotweed typically grows close to the ground, reaching a height of 10 to 40 centimeters.
  • Leaves: The leaves are lance-shaped and arranged alternately along the stems.
  • Stems: The stems are prostrate and often form dense mats.

2. Flowers:

  • Inflorescence: The small, greenish-white to pink flowers are arranged in spikes at the ends of stems.
  • Blooming Period: Common knotweed blooms from late spring to early autumn.

3. Habitat:

  • Commonly found in a variety of habitats, including lawns, gardens, roadsides, and disturbed areas.
  • Thrives in well-drained soils and is adapted to both dry and moist conditions.

Ecological Roles:

1. Soil Stabilization:

  • Common knotweed's dense mat-forming growth helps stabilize disturbed soils, preventing erosion.

2. Pioneer Species:

  • Often one of the first plants to colonize disturbed areas, common knotweed plays a role as a pioneer species.

3. Tolerance to Disturbance:

  • The plant is adapted to human-altered environments, making it resilient in urban and agricultural settings.

Invasive Characteristics:

1. Rapid Spread:

  • Common knotweed has a prolific seed production and can spread rapidly, forming extensive colonies.

2. Competition with Natives:

  • In some regions, common knotweed has been observed to outcompete native vegetation, impacting local plant communities.

Control and Management:

1. Cultural Practices:

  • Promoting healthy and dense vegetation in lawns and gardens can help suppress common knotweed growth.
  • Regular mowing or cultivation may be effective in smaller areas.

2. Mechanical Methods:

  • Hand-pulling or hoeing can be employed for small infestations.
  • Ensuring the removal of the entire plant, including roots, is important to prevent regrowth.

3. Herbicide Use:

  • Selective herbicides targeting broadleaf weeds can be used for control in lawns and non-crop areas.
  • Care must be taken to minimize harm to desirable plants.

4. Prevention:

  • Preventing the introduction and spread of common knotweed seeds to new areas is crucial for management.