Spotting the Common Weeds on Your Course

Singapore’s warm and humid tropical climate is conducive to the growth of various types of weeds that can invade turfgrass, lawns, parks, and gardens. Understanding these weeds and their characteristics is essential for effective turf management and maintaining healthy green spaces. Old World Diamond Flower, Spurge, and Threeflower Beggarweed  are common broadleaf weeds found in Singapore. We’ll explore their identifying features, growth habits, management strategies, and the importance of pre-emergent and post-emergent herbicide programs in maintaining weed-free turf.

Old World Diamond Flower  (Hedyotis corymbose)

Identification: A small, fast-growing weed, characterized by its four-sided stems and small white flowers. Key Features: Leaves: Opposite, linear to lance-shaped, with rough edges. Stems: Square-shaped, slender, and often tinged with purple. Flowers: Tiny, white, star-shaped, and clustered at the ends of branches. Growth Habit:  It prefers open, sunny areas and can tolerate a range of soil types. It reproduces by seeds and can spread rapidly if not controlled

Spurge (Euphorbia spp.)

Identification: A low-growing, prostrate weed that forms dense mats in turfgrass. Commonly found in dry or sandy soil, areas with low nutrients, and compacted and undisturbed sites. A key identifying feature is the milky white sap that oozes when the stems are broken. Key Features: Leaves: Small, oval, often with a reddish spot in the center. Stems: Red to purple, branching, and spreading along the ground. Flowers: Tiny, pinkish-white, found in clusters at leaf axils. Growth Habit: Reproduces by seeds and thrives in compacted, dry, or disturbed soils. Its rapid growth and ability to tolerate poor conditions make it a persistent weed.

Threeflower Beggarweed (Desmodium triflorum L.)

Identification: A distinctive trifoliate (three-part) leaves. It is commonly found in golf course roughs, undisturbed areas, roadsides, and neglected turfgrass. Key Features: Leaves: Trifoliate, with elliptical leaflets that are hairy on both sides. Stems: Erect, woody, and branching, with fine hairs. Flowers: Pea-shaped, small, pink to purple, growing in clusters along the stem. Growth Habit: Perennial weed that reproduces through seeds and can grow up to 1 meter tall. Its seeds are notorious for sticking to clothing, animals, and equipment, facilitating spread.

Management:

• Cultural Control: Ensure healthy, dense turf through proper fertilization and irrigation to prevent invasion.

• Mechanical Control: Use regular hand-pulling or hoeing for small infestations.

Herbicide Program:

• Pre-emergent: Apply Barricade (Prodiamine) to prevent seed germination.

• Post-emergent: Use Casper (Prosulfuron + Dicamba) for effective control of established weeds.

   

Importance of a Pre-Emergent and Post-Emergent Herbicide Program

An integrated pre-emergent and post-emergent herbicide program is crucial for effective and long-term weed control in Singapore’s turf and green spaces. These practices work synergistically to:

• Prevent New Weeds: Pre-emergent herbicides inhibit seed germination and prevent new weeds from establishing.

• Eliminate Existing Weeds: Post-emergent herbicides target weeds that have already germinated and are actively growing.

• Minimize Weed Pressure: Consistent use of both approaches reduces the weed seed bank in the soil, lowering future infestations.

• Improve Turf Health: Maintaining weed-free turf allows grass to thrive without competition for nutrients, water, and sunlight.

Implementing a strategic herbicide program alongside proper cultural practices like mowing, fertilization, and irrigation ensures a healthy and aesthetically pleasing turf quality.

By understanding the characteristics of common weeds and adopting a comprehensive management program, turf managers and landscapers in Singapore can effectively mitigate weed problems and promote greener, healthier spaces.