A daisy but not from Singapore

A very bad weed along creeks, rapidly invades, somewhat resistant to glyphosate-based herbicides, becomes a dense monoculture. Very difficult to remove. Native to South America. Stems are rounded, sometimes hairy, sometimes reddish. The stems can trail (grow) to 4 m, rooting at the nodes. The main stem supports secondary short flowering branches. It has an unpleasant odour similar to celery. Singapore Daisy is on the International Union for Conservation of Nature’s list of 100 of the World’s Worst Invasive Alien Species. Leaves are opposite, with three lobes and serrated margins. All parts of the plant must be removed, cooked out in mulch piles or taken off site. The daisy flower-heads are born on single stalks, with up to 13 petals (ray florets). Seeds are capped with a crown of short scales. Synonym is Wedelia trilobata.

Photo: Robert Whyte

Flowers and Foliage. Photo: Robert Whyte

Flower close-up. Photo: Robert Whyte