Atrazine (Bonus, Purge, others) is labeled for centipedegrass, zoysiagrass, St. Augustinegrass and bermudagrass. Atrazine can be applied to actively growing and dormant centipedegrass or St. Augustinegrass but bermudagrass can be injured if treated while actively growing. Simazine (WynStar, others) may be applied to actively growing bermudagrass, centipedegrass, St. Augustinegrass and zoysiagrass lawns. Atrazine and simazine have excellent preemergence activity on annual bluegrass but soil residual is generally shorter (four to six weeks) compared to aforementioned herbicides. Several atrazine and simazine products are not labeled for residential lawns and turf managers should check labels for further information before use. Put out in September
