Tufted Grass Weeds in Sub-tropical Turfgrass

Introduction

Tufted grassy weeds are from the Poaceae family. Unlike problem grasses that creep into the lawn, clumping and tufted grasses have a restricted horizontal spread. After mowing they leave an obvious stub behind. In coarser species, such as crowsfoot, this can create a trip hazard.

Early identification and swift action can prevent a serious problem developing. In small numbers, these grasses are relatively easy to dig out. However, clumping or tufted grass weeds usually spread freely from seed and quickly multiply. For this reason, it is particularly important to maintain a regular mowing schedule to prevent these grasses from heading. If a headed tufted grass is to be removed or mowed, and if plant numbers are small, clip the head and seal it in a bag to avoid inadvertently re-seeding the area.

Compacted sites

Three grass weeds, elastic grass, dwarf Parramattta grass and crowsfoot, establish commonly in areas subjected to wear. Their growth is favoured by a tolerance of compacted soil and a lack of competition from other species. The stalks of these grasses are resistant to cutting with mower blades and remain on the plant after the pass of the mower. Once hardened off, they also cope with trampling.

Shade areas

Winter grass is a problem grass of both shady and sunny areas. Its seed germination is favoured by exposure to light. However, the mechanism of germination in winter grass is complex, so that long duration exposure to low light intensities has the same effect as a short exposure to high light intensity. This enables the plant to succeed over a wide range of light levels.

Lawns are often subjected to additional shading in winter, arising from the sun’s lower angle in the sky and shorter day lengths. Turfgrass species with a relatively low shade tolerance, such as blue couch and green couch, may thrive in a location in summer, but thin markedly in winter, allowing winter grass to become dominant.

Prime conditions

The presence of common paspalum in a lawn can be a sign of good growing conditions – for both the turf grass and the weed. Common paspalum is a clumping grass and will slowly spread laterally and via seed if not controlled.

More on tufted grass weeds

Growing in compacted areas:

• elastic grass or wire grass (Eragrostis tenuifolia)
• Parramatta grass (dwarf) or rat’s tail grass (Sporobolus africanus)
• crowsfoot or goosegrass (Eleusine indica)

Growing in shaded areas (and sun):

• winter grass (Poa annua)

Growing in prime conditions:

• paspalum or common paspalum (Paspalum dilatatum)