People can argue about anything, including the best definition of a weed. However, every land manager I know can agree about their loathing for invasive thistles. Unfortunately, a new species has made its way to North America and found an ideal habitat on the stark hillsides of Hells Canyon.

It's one thing to identify a weed, and another to know what to do about it. Find out what weeds to target in Madison, Ada, Twin Falls, Cassia and Bonner counties.

Which weeds are most problematic in Idaho's grain production systems? We asked.

Purple loosestrife (Lythrum salicaria) is a semiaquatic perennial plant that is native to Europe and can be purchased (illegally) as an ornamental.

Clue: This plant resembles an alfalfa plant after a migration of grasshoppers has stripped all the leaves off.

Palmer amaranth is a prolific seed producer that competes with growing space for corn, soybeans and other commodities important to the dairy industry. An unlikely risk management tool to reduce this weed’s presence in fields is proper manure handling.

Traditional annuals and more exotic cocktail cover-crop mixtures can make great forage for cattle on a temporary basis, but over the long haul, a good stand of perennial pasture can be the best choice.

Weed resistance? Better bring your A game.