Poisonous yew plants have killed elk in Southern Idaho again — this time north of Boise

Yew, the toxic landscaping plant, has killed about a half-dozen elk in the Horseshoe Bend and Garden Valley areas this month, Idaho Fish and Game says.

The plant that killed elk near Horseshoe Bend has been identified and removed. It was a long-standing plant but the new homeowners were unaware of its toxicity to wildlife, said Rick Ward, regional wildlife manager for Idaho Fish and Game’s Nampa region.

The source of the yew near Garden Valley hasn’t been identified, Ward said.

With the mild winter, Ward theorizes that a late hunt to deal with damage elk have done to private property has pushed some animals close to town in Horseshoe Bend.

“That Japanese yew had been there for quite some time,” Ward said.

Landscaping yews aren’t native to Idaho and all are toxic to wildlife — most are varieties of Japanese or European/English yews. Yews are unusual among evergreens in that they thrive in partial sun and shade commonly found on the north side of properties. There is a native yew, the Pacific or western yew, that is found in Washington and Valley counties and points north in Idaho. However, it doesn’t work well for landscaping (it requires a lot of water). The native yew has trace amounts of poison but is used safely as winter food by moose, elk and deer.

Landscaping yews were cited in the deaths of dozens of wildlife in the Boise area in the harsh winter of 2016-17, including 50 pronghorn in one incident in Payette. That prompted a public-education effort that led some stores and neighborhoods to change their approach to the plants. Many yews were removed, while other homeowners learned to cover them to keep wildlife away. But a push by conservationists to ban the plants through the Idaho State Department of Agriculture failed.

Ward is hopeful that yew won’t be as big of a factor the next time snow drives wildlife into the Treasure Valley.

“It’s definitely gotten better,” he said. “We won’t really know until we have another big winter. ... We hope it’s less likely to be placed in places like the Foothills than it used to be. I was really surprised two years ago to find out how widespread it was.”

Last month, a mule deer fawn died of yew poisoning near Rexburg in East Idaho, Fish and Game reported.

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