Thistles have been slow to grow this year, but with many a metre high or more and bursting into flower, now is a good time to tackle them before they set and spread their seed.
"Weed control in grassland is usually done in the spring, when there are a lot of other significant jobs to be done, not least lambing and calving," says Brent Gibbon, grassland agronomy manager for Dow AgroSciences.
"Getting on top of tough perennial weeds now, when there is a little less work to do and weather conditions are moist and warm, might be a better option."
Tall, flowering thistles need to be cut down first, as they are too big and not at the right vegetative stage to be sprayed with translocated herbicides.
Then left for three weeks to regrow, the fresh leaves will be big enough to provide the ideal target for a spray.
"Where thistles are the main problem, Thistlex is the best product to use. If there is a broader range of weeds involved, PastorPro is good or Forefront T – just in grazing situations or after the last hay or silage cut," advises Mr. Gibbon.
"All three products will take out all species of thistles, such as Spear, Creeping or Marsh. And tackling them now reduces the amount of new plants that will germinate from seed this year, and reduces what has to be done next spring."
