Thistle

Thistle

From Page A1

Rappahannock.

In particular, VDOT and its independent contractors, who actually do the spraying, are fighting the hardy thistle (Onopordum acanthium), which Watson describes without poesy as “a noxious weed for its destructive invasiveness which is detrimental to adjoining agriculture.”

Apparently, according to VDOT, livestock will not eat the prickly plant, but thistles in a pasture will crowd out all other vegetation, including turf, spreading “like wildfire,” said Watson.

With their heads of white, yellow’, pink, or purple flowers, the thistle presents a lovely sight to some horticulturists’ eyes. While it is the enduring symbol of the Scottish people’s famous ability to endure, the thistle is not to everybody’s taste, including horses and cows.

“You can have a nice pasture but once thistles get in, livestock won’t go there,” Watson adds.

June is the end of the thistle’s flowering season, when the plant starts going to seed. It is just the time for VDOT’s contractors to hook up their sprayers and blast the parent plants before the wind can carry the seeds to fields and meadows adjoining the state roads.

“There are so many thistles that we can’t get all of them, but we try,” said Watson, who is an authority on noxious weeds and plants.

Chemicals used

VDOT deploys a chemical combination of 'Garlon-3A' and Vanquish, which are broad leaf weed killers that do not hurt turf, according to Watson, who describes VDOT’s thistle killing potion as “fairly benign,” comparing it in an apothecary’s term to an “over-the-counter drug,” while a stronger weed killer would be a “prescription drug.”

This thistle solution, Watson said, “contains the EPA’s lowest level of warning of any (weed killer).” It works through the thistle to its roots and kills quickly—in days, Watson says.

Dr. Marvin Lawson agrees, sort of and up to a point.

Lawson is the Virginia