Anyone who’s paying attention has likely noticed that whitetop — also known as “hoary cress” — is all over Wright’s Mesa. While whitetop has been a problem on the local landscape for the last several years, San Miguel County Vegetation Control Specialist Ron Mabry said now whitetop is worse than ever.
“It definitely seems to have just exploded this year,” he said.
Whitetop is a white, fluffy looking invasive weed that grows in patches. It has a distinctive umbrella-type flower head on it.
Mabry said he doesn’t believe whitetop’s appearance is necessarily an indication of poor soils health. He said the weed becomes more established when grass is absent. He said grass gives it some competition.
Last year, Mabry said, much of the whitetop didn’t get treated because of drought. Also, some of the grass dying during the dry spell likely contributed to the weed flourishing.
Now, with all of the recent rains, whitetop seems to be making a strong comeback.
Could goats be a natural answer? Mabry said they sometimes can help. He said goats typically eat what is not grass — in other words, weeds.
Mostly, though, goats keep the weeds mowed down and prevent them from going to seed.
“They don’t get rid of perennial weeds, just annual ones,” he said. “I’ve used them on Canada Thistle, but you have to put them back in the same area in two to three weeks.”
There is still time to spray whitetop, Mabry said, though ideally spraying should be done when the plant is young.
According to him, the spray is not toxic.
“It’s a dry formulation you mix into water,” he said. “It’s very low to no volatility.”
He said a landowner can put livestock back on a pasture after the spray has dried. He said a horse won’t touch whitetop because of its bitter taste, but cattle will eat the plant when it’s young, before it flowers.
Mabry said if plants are still white, spraying can work. If they’ve turned yellow or brown, the plant has gone to seed and no spray will help.
Usually, San Miguel County has a cost-sharing program to help landowners combat invasive weeds. This year, however, Mabry said his office got no support from the state. He said his fund for cost sharing has dwindled to a balance of $1,500.
Mabry said whitetop can be challenging to eradicate. The seeds are viable for five to six years, and it can take several years to completely be rid of it, which can be expensive.
He said the current state of whitetop in local pastures is “depressing.”
“I will be the first one to tell you,” he said. “When I see it all out there, and there’s nothing I can do about it. … It’s not going to go away. People need to do something as far as treating it.”
Mabry said he urges all landowners to be concerned about whitetop. At the same time, he said he is not permitted to require spraying or eradication of the weed.
“It’s not a weed I can enforce on. I can’t force anybody. I can ask, but I can’t make them do it,” he said.