Winter cleaning of Silver grass significantly increases the clover composition and maintains the pasture comparatively free of silver grass for up to 5 years after spraying.  Silver grass is a voracious user of water and nutrients but has very low nutritional value to grazing stock.  Winter Cleaning involves spraying an improved pasture with a combination of Simazine and Paraquat.  It also partially controls other annual grasses such as brome grass, barley grass and winter grass.   The objective is to kill the standing mass of silver grass and prevent the emergence of successive germinating silver grass seed for up to three months after application. It has no adverse effect on sown perennial grass or clover in spring.  When there is no competition the clover present in the pasture spreads into the gaps, thickens up and significantly improves the pasture quality. Optimal times to spray are; May / June if there has been an early or “normal” autumn break. Mid August to mid September if there is a late or stop start autumn break. Successful spray program in these months is due to sufficient soil moisture at the time of Spraying,  & favorable growing conditions.There is no impact on sown perennial grasses after spraying. Spraying should not continue after mid September as it may reduce the flowering and seed set of early maturing clovers such as Trikkala.  If spraying late, consider spaying a greater number of paddocks, as there is usually abundant feed in other paddocks that can carry the extra stock numbers. During 14 day withholding period after spraying. When spraying late it is critical to crash graze the pasture down to a height of less than 5cm before spraying. This increases the efficacy of the spray program.