At the recent Yellow Gum Festival at Bannockburn Recreation Reserve there was a small demonstration of a flame weeder. These tools run on gas and the flame is passed over weeds to destroy the plant’s cells. Flame weeders are not successful on all weeds and will require more than one pass.
The oxalis with large yellow flowers, Oxalis pes-capre, reproduces by bulbils. Soil disturbance spreads the bulbils so digging them out is usually unsuccessful and the plants will survive fire. Chemical control is the most common control method and is most effective if applied in June or July when the oxalis is actively growing.
As with most weed control timing is everything and you need to understand the plant’s life cycle. Flame weeders are not useful for perennial grasses like kikuyu but may be worth trying on oxalis if you are prepared to go over the new leaves on a regular basis. The aim is to weaken the bulbs and exhaust them allowing other plants to take over. These weeders are useful for annual weeds before seed set but if using them near dry grass or leaves watch don’t start a fire.