COLLEGE STATION – Farmers and ranchers who passed on controlling slow-growing weeds this spring may now have reason for regret, said a Texas A&M AgriLife Extension Service expert.
“If you’re standing out in your hay meadow or pasture and wish you had another inch of rain, that inch of rain may have been that which was sacrificed to early season weed issues,” said Dr. Paul Baumann, AgriLife Extension state weed specialist, College Station.
The cooler-than-usual spring slowed the growth of weeds and warm-season grasses alike, and many producers may have put off spraying or shredding weeds, Baumann said. But now that the drought is re-strengthening in nearly all of Texas, many weeds species are coming back with a vengeance, robbing improved pasture grasses of moisture and nutrients.
Weeds that always pose early season competition for improved forage grass areas of Texas include annual broomweed, wooly croton, goat weed, bitter sneezeweed and a number of other annual weeds, he said.
Many perennial weeds that flourish during a drought are troublesome but usually don’t pose as much as a challenge to improved pastures as the annuals, according to Baumann.
“For the perennials, we’re talking about silverleaf nightshade, dog fennel, horse nettle, Texas bull nettle and weeds like that,” he said. “They flourish because they have a well-developed, deeper root system that makes them less prone to moisture deficiency, particularly in the lower soil profile.”
But the early season annuals like goat weed, dove weed or wooly croton have shallower root systems that vie for the same shallow soil moisture that Bermuda grass and other improved pastures are trying to capture, he said.
For producers who did not do any early season weed control and are now seeing a flush of annual weeds in their pastures, Baumann recommended waiting until a good rain before doing anything.
“For the weeds that are still out there that are less than 6 to 8 inches tall, wait until you get a little bit of rain on them before spraying because they are going to be less susceptible to herbicide if they are moisture stressed,” he said.
Leaving weeds uncontrolled, even if there is not much grass growth, is not a good choice, Baumann said. This is because they are going to continue to compete for moisture during a very stressful time of year, as well as eventually deposit a seed load that will last for years to come.
Also, if there is a mid-season rain, the weeds will spring back to life and compete with pasture grasses at a very critical time of year, he said.