Kansas Ag News Headlines Hate Dandelions? Act Now Kansas Ag Connection - 11/19/2009 The month is the most effective time to control some of the worst broadleaf weeds that commonly infest central U.S. lawns. "Young weeds are always the easiest to control. So -- believe it or not - that's one reason early November is a good time to apply broadleaf weed herbicides in our region," said Ward Upham, horticulturist with Kansas State University Research and Extension. Another factor makes such applications especially effective. "At this time of year, cool-season weeds are actively moving materials from their leaves to their roots, storing food for winter," Upham said. "They're so intent on this that they'll even translocate a herbicide application. That's why you can finally kill dandelions completely - from their deep tap root on up." Many dandelions are young now because the weed typically puts out a flush of new plants during early to mid fall, the horticulturist said. The winter annuals among the broadleaf weeds (e.g., henbit, chickweed) go to seed much earlier in the growing season. But, that seed germinates in the same year during mid to late fall. "That's why winter annuals can get off to such a strong start in spring," Upham said. "Just before winter arrives, they sprout, grow a little and develop a root system. Then they lose their new top growth to winter's cold. But, having already gotten a head start, they're raring to grow the following spring." Even with November's good timing, however, herbicide applications can fail, he warned. The reasons: -- The better the weed is growing, the more herbicide it will move from leaves to root. And, vice versa. -- Broadleaf weed herbicides perform best if applied on a day when temperatures are 50 degrees or higher. Colder temperatures slow or stop the herbicides' action. The herbicide 2,4-D is a good choice for November applications, Upham said. Other effective choices - sold under such trade names as Trimec, Weed-B-Gon and Weed-Out -- combine 2,4-D with both MCPP and Dicamba. Another option, marketed as Weed Free Zone and Speed Zone, combines those three active ingredients with yet another - carfentrazone -- so it can provide the quickest results of all, especially as temperatures approach 50 F. More from this state at: Kansas Ag Connection Copyright © 2010 - USAgNet.com. All Rights Reserved.