Queensland blue grass

Dichanthium sericeum

Dichanthium sericeum, commonly known as hairy crabgrass or tropical finger grass, is a warm-season annual grass belonging to the Poaceae family. It is native to tropical and subtropical regions and is often found in lawns, gardens, and disturbed areas. Here's an informative description, including detailed information on its appearance, identification, and management:

Appearance:

  1. Growth Form:

    • Hairy crabgrass is an annual grass that typically forms low, spreading clumps.

  2. Leaves:

    • The leaves are light green, hairy, and have a distinctive folded or V-shaped vernation (the arrangement of young leaves in the bud).
    • Leaf blades are flat, broad, and can vary in length.

  3. Inflorescence:

    • The flowering stems produce characteristic finger-like spikes (racemes) that give the grass its common name.

  4. Seedheads:

    • Seedheads are composed of numerous small, bead-like seeds.

Identification:

  1. Vernation:

    • The V-shaped vernation of the leaves, especially when they are young, is a key identifier.

  2. Hairy Leaves:

    • The presence of fine hairs on the leaves contributes to the "hairy" aspect of its common name.

  3. Seedhead Structure:

    • The finger-like seedheads are distinctive and contribute to the identification of hairy crabgrass.

Habitat and Distribution:

  1. Habitat:

    • Hairy crabgrass is commonly found in warm-season climates and is adaptable to various soil types.
    • It thrives in lawns, gardens, roadsides, and other disturbed areas.

  2. Distribution:

    • It is native to tropical and subtropical regions but has become widespread in many parts of the world.

Management:

  1. Cultural Practices:

    • Maintaining a healthy, dense turf through proper mowing and watering practices can help reduce the establishment of hairy crabgrass.

  2. Pre-Emergent Herbicides:

    • Pre-emergent herbicides applied in the spring can be effective in preventing the germination of hairy crabgrass seeds.

  3. Post-Emergent Herbicides:

    • Post-emergent herbicides labeled for grass control can be used if hairy crabgrass has already emerged.

  4. Hand Pulling:

    • For small infestations, hand pulling or digging out the plants can be effective.

  5. Seeding or Sodding:

    • Overseeding or sodding with desirable grass species can help reduce open spaces for hairy crabgrass to establish.

  6. Mowing Height:

    • Maintaining a higher mowing height can help shade the soil and reduce the likelihood of hairy crabgrass establishment.