Common Names: Singapore daisy, Creeping ox-eye, Trailing daisy, and Wedelia (English), Wedeliya (Sinhala)
Synonyms: Complaya trilobata (L.) Strother Thelechitonia trilobata (L.) H.Rob. & Cuatrec, Wedelia carnosa Rich, Wedelia paludosa DC, Wedelia trilobata (L.) Hitchc
Taxonomic notes: Although Sphagneticola trilobata is the currently accepted name for this species, it is widely known as Wedelia trilobata which is the previous name. The basonym is Siphium trilobatum L., and the species has been transferred to numerous genera including Compalaya, Sphagneticola, Thelechitonia, and Verbesina (CABI 2015).
S. trilobata is perennial and grows to 45-60 cm high. Stems are green, rounded, rooting at nodes, 10-30 cm long, the flowering portions ascending, covered with dense hairs, sometimes sparsely hairy. Leaves are fleshy, usually 4-9 cm long (1.5-) 2-5 cm wide, simple obovate, irregularly toothed or serrate, usually with a pair of lateral lobes. The leaf arrangement is opposite to subopposite. Leaves are green in colour. S. trilobata usually flowers throughout the year. Flowers, solitary, arise in the leaf axils. Stalks 3-10 cm long, covering bell-shaped or hemispherical, ray florets often 8-13 per head, yellow in colour; disk corolla 4-5 mm long. Fruits are inconspicuous (CABI 2015, Wagner et al., 1996)
Total height: Height is between 45-60 cm
History and introduction:
S. trilobata has been repeatedly introduced to other countries from its native region Central America as an ornamental plant although the original dates of introduction are rarely known. Introduction of this plant to Sri Lanka is believed to have been in late 1970’s. It has been introduced as an ornamental plant from Singapore where the plant had aready been introduced as an ornamental plant earlier (personal communication).
Since its introduction to other parts of the world, S. trilobata has gained a wide distribution in the world. In Sri Lanka, it is widespread across the wet zone and coastal zone up to the upcountry regions of around 1000 m above sea level.
Dispersal and reproduction:
S. trilobata usually reproduces vegetatively (HEAR, 2008) but viable seeds may also be present in the soil (Macanawai, 2013). The propagules are very often dispersed intentionally by people, or unintentionally in garden waste. It is commonly planted as an ornamental plant (Englberger, 2009). Usually stems form new plants where they touch the ground and pieces readily take root. Plants usually develop few fertile seeds. They are commonly spread through the dumping of garden waste (PIER, 2003).
Impact on native species and habitats:
When Sphagneticola trilobata becomes established in plantations, it competes with crops for nutrients, light and water, and reduces crop yields. It rapidly escapes from gardens to roadsides and plantations, where it can overgrow plants and develop into a thick cover. It forms dense ground cover, crowding out or preventing regeneration of other species (PIER, 2003).
Direct exploitation/destruction of native species:
Direct exploitation of native species has not been reported for this species.
Current Uses: Commonly used as an ornamental plant and groundcover. Recent studies suggested the use of this plant in industrial waste water treatments (Dissanayake et al. 2002)
Natural Threats (Pests): Not known.
Prevention and Control:
No control measures have been taken for this species in Sri Lanka. However, growth of S. trilobata can be controlled by carefully managing nitrogen fertilizer and irrigation. The importation and spread of S. trilobata can be significantly reduced by public education on the aggressive nature of the species. S. trilobata can be effectively controlled by removing the top few centimetres of soil using a suitable tool such as a fire hole, with the aim of removing the soil-stored seed bank. Repeated hand pulling or following up with herbicide application is often necessary. In addition, burning can also be practiced.
The spread of S. trilobata may be controlled by spraying metsulfuron-methyl herbicide (HEAR, 2008). The addition of a suitable wetting agent is also important (HEAR, 2008).