FILE: TOLL-FREE CALL 0508 299 299 HORNED Oxalis corniculata oxalis, though nothing similar reported DESCRIPTION in New Zealand. This species of oxalis is the larger one HABITAT and is the one of more concern. The Horned oxalis is found across most of other smaller, common relative that the world, and is common throughout looks similar is creeping oxalis (Oxalis New Zealand. It particularly favours exilis), which is a native oxalis. gardens as well as closely grazed Horned oxalis is a perennial weed pastures. It also appears in , species that grows low to the ground. ornamental and sporting turf, though the smaller, native creeping oxalis is The flowers are yellow, and grow up more common in those locations in to about 1cm in diameter, sometimes NZ. singly, but more often in clusters of from two up to five flowers per stalk. It HERBICIDE CONTROL flowers from December to January in Horned oxalis, like most of the most locations. oxalis species, is able to tolerate are trifoliate, which means they most of the commonly used are made up of three leaflets each of selective herbicides, and results with which is notched on the outer end. common sprays like MCPA and 2,4- This forms the classic ‘three-leafed- D can be very disappointing, as can ’ shape. The leaves are generally treatment with sprays containing up to 20mm across. clopyralid. The similar native creeping oxalis The one well-proven herbicide mentioned above also has yellow active is triclopyr, whether alone flowers and trifoliate leaves but it’s or in combination with picloram. smaller in all respects (e.g. the flowers However the products containing are normally only up to 10mm across). picloram as well as the triclopyr The creeping oxalis flowers are also (e.g. GrassMate) will cause severe smaller, and nearly always appear only clover damage, whereas those singly rather than in clusters. containing triclopyr alone are far Horned oxalis spreads readily because less damaging to clover, especially of its stolons, which is a stem that at the moderate application rates creeps along the ground and produces required as follows: new roots at the stem nodes. This Spot Spraying allows the to form quite dense • Triclo at 2ml/10m2 patches in pastures, turf and lawns. The plant also spreads via seeds, but Boom Spraying does not have the underground bulbs • Triclo at 2L/Ha found on some other similar species In all cases when spraying, for (e.g. fishtail oxalis, Bermuda buttercup, best results add SprayWetter pink shamrock and others) penetrant at 10ml/10L water to There have been reports from Australia ensure thorough penetration of the of sheep being poisoned by horned herbicide into the plant.

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