BOISE, Idaho — Homeowner Jerry Smith and Idaho Fish and Game conservation officer Ben Cadwallader watched a mule deer eat from the poisonous yew bush in Smith’s back yard early this month. They followed as the deer ran over a hill.
“And it was dead,” Smith said. “They die that fast. It was not 10 minutes and that deer was dead. … It was a frustrating situation for us because we’ve worked hard at trying to help the animals stay alive for all the years we’ve been there.”
Smith and his wife, Donna, have lived in the Barber Valley east of Boise for 46 years. They learned in January that the three yew bushes they planted in their front yard were poisonous after hearing about the deaths of seven elk that ingested the plant in a nearby neighborhood. The Smiths covered those plants with shrink wrap and made plans to rip them out this spring.
But they didn’t realize that the transplanted bush in their back yard was a yew, a plant with many varieties — nearly all of them toxic to wildlife, people and dogs. Seven mule deer died after presumably eating from that bush, including two that collapsed in the Smiths’ yard and led the couple to contact Fish and Game.
Smith and two neighbors immediately took a chainsaw to the bush and removed it. They removed the three in the front yard, too.
“I’ll do anything I can to get the word out,” Smith said. “It’s a deadly plant and we should not have it — we should not have it in the state of Idaho at all. … It’s devastating to come out and find dead deer around your house and think you did it.”
Yew poisoning has been cited as the cause of death for at least 28 elk, 50 pronghorn and an unknown number of deer this winter as more wild animals than usual have filtered into populated areas in search of food that isn’t covered with snow.
The elk deaths have occurred in six communities from Boise (eight total) to Preston. The 50 pronghorn died in one incident in Payette. Eight mule deer died this month in East Boise — the seven at Smith’s house.
All of the deaths in the Treasure Valley have been attributed to landscape plantings at homes. Landscaping yews aren’t native to Idaho — most are varieties of Japanese or European/English yews. A similar problem occurred last winter in the Ketchum area, leading Blaine County to ban the plant.
Evin Oneale, a regional conservation educator for Fish and Game based in Nampa, said this is the first time he’s heard of yew-wildlife incidents in the Treasure Valley. He’s been here more than 20 years.
But as homes encroach more on the winter range of elk and deer and severe winters like this one push the animals to even lower elevations than usual, the issue likely will come up again.
“(The incidents) are in a lot of areas where 10 years ago there weren’t houses,” Oneale said. “That just gives them more opportunity to come into contact with this plant because it’s so prevalent in the landscaping business.”
Dennis Fix, who owns a landscaping business in Boise, wrestled with how to handle yews at his business after the elk deaths. His first inclination was to stop stocking them, but he sells between $20,000 and $40,000 worth of the plants annually.
He has informed customers in the past about toxicity in relation to people and pets but didn’t anticipate the threat to wildlife, he said. He plans to keep the plant in his inventory but increase education to those who want to buy it, including signage. He also plans “more screening to prevent sale of yews to big-game zones within our city,” he said.
Fix also is making the public an offer: Bring him a yew you’ve removed from your yard, regardless of where you purchased it, and you’ll get a $30 credit toward purchase of a replacement shrub. The company will dispose of the yew.
Fix estimates a quarter to a third of his customers have a yew in their yards. Yews are unusual among evergreens in that they thrive in partial sun and shade commonly found on the north side of properties. He sells yews for about $40-$50 in the five-gallon size to about $150 for larger versions.
“They’re not popular like a rose would be, where everyone’s got one, but they do fit a niche,” Fix said. “… You put these in the same spot as a Japanese maple or a hosta. You drop a yew in there to hold a little interest in the winter.”
2,000 years of poison
It’s surprising that this winter’s yew-related deaths came as such a surprise.
The toxicity of the plant is no secret. More than 2,000 years ago, Julius Caesar wrote about a king committing suicide by yew in his book about the Gallic Wars. Yews are known as some of the most toxic plants in Europe, said Lynn Kinter, the lead botanist at Idaho Fish and Game. Japanese yews are even more toxic, she said.
Despite that, yews became popular in America beginning in the 1920s, she said.
“Maybe that knowledge got lost to some extent,” Kinter said. “Maybe people didn’t realize quite how poisonous they were.”
Blaine County Commissioner Angenie McCleary said she had never heard of yew killing wildlife before January 2016, when 11 elk died in a cemetery. More elk died shortly afterward in Sun Valley.
Within a month, McCleary and her fellow commissioners made “possession, planting or sale” of several yew species a crime in the county’s unincorporated areas. The law has teeth. Violations are a misdemeanor. That means people who keep yews on their property risk up to a year in jail, though that stiff of a penalty is unlikely.
The ban isn’t meant as a punitive measure, McCleary said. In fact, the county hasn’t cited anyone for breaking the yew law and doesn’t patrol neighborhoods looking for rogue plants.
The law appears to have been effective. Despite a harsh winter that’s turned wildlife into regular inhabitants of neighborhoods and city streets, the first yew-related death reported in Blaine County occurred this week when a moose died, McCleary said.
In the Treasure Valley, yews flew so far under the radar in recent years that they were placed on the approved plant list for Harris Ranch when the development along the East Boise Foothills began in 2008. That’s a neighborhood so wildlife-conscious that homeowners pay a $100 annual fee toward wildlife projects.
“We had (the list) reviewed by all of our wildlife consultants that wrote the mitigation plan as well as Fish and Game,” said Doug Fowler, project manager for Harris Ranch.
When Harris Ranch officials were informed that yew was responsible for the elk deaths near Table Rock, they pulled it from the list. Residents have been asked to cover the plants with burlap for the winter if they’re unwilling to remove them.
Mark Drew, the wildlife veterinarian for Idaho Fish and Game, has examined some of the yew-poisoned animals to determine the cause of death. The toxin — taxine B — causes cardiac arrest, he said.
And while many poisonous substances are distasteful enough to discourage consumption, the animals Drew examined were full of yew.
“These are evergreen species — in a stark, white landscape where everything is black and white or brown, if something looks green, it probably looks tasty,” he said.
Even if the animals limited themselves to a few bites, yew could kill them. Studies show that it takes 30 grams of leaves to kill a dog and about 500 grams to kill cattle, Drew said.
“You’re talking a half cup, a cup full (for big game),” he said. “So not much.”
The animals he’s seen have ingested “cups and cups” of yew material. The stems and leaves are poisonous, as well as the seeds inside the red berries some yews produce in summer and fall.
“They die pretty quickly because their heart stops,” Drew said. “Some of those animals died with yew leaves in their oral cavities and esophagus.”
‘A minefield’ of toxic plants
Drew hopes the animal deaths this year at least lead homeowners to ask questions about their plants that they never have before.
“We don’t stop to think, ‘Is this potentially poisonous?’” he said. “It’s not even in the realm of possibility of questions we would ask. We just need to let people know that some of the plants used in landscaping are potentially toxic, and if you’re in a situation where ungulates (deer, elk, horses and many other species) are potentially using your yard, your neighborhood, maybe we’ve got to think about that.”
Others prefer a more drastic response. To them, there’s no place in a wildlife-loving state for a wildlife-killing plant.
Angela Rossmann of advocacy group Great Old Broads for Wilderness has spent the past few weeks calling government agencies, neighborhood associations and garden centers trying to increase awareness and build momentum toward a yew ban.
“We’re small enough that if everybody works on this, we could make it go away,” Rossmann said.
Her allies include the Ada County Fish and Game League, a sportsman group that dates to the 1920s. John Caywood of Boise, the group’s president, says wildlife is being wasted by a plant that benefits few. At the least, he’d like to see more of what Harris Ranch is doing — making the plant unwelcome in developments along the Foothills.
“We just think it would be a great idea,” Caywood said, “if native wildlife didn’t have to run through a minefield of exotic, introduced, poisonous plants in people’s yards.”
Educate or regulate?
So far, local governments are reluctant to ban yews. McCleary, the county commissioner, said she’s aware of no law in Idaho similar to the one Blaine County passed last year.
Payette County prefers to use education to avoid further wildlife deaths, Deputy County Clerk Christine Poe said.
Calls from people concerned about poisoning wildlife have trickled into Ada County’s offices over the past few weeks, spokeswoman Kate McGwire said, and the county’s weed control team is hosting an online survey to find out how pervasive yews are and if people know they’re dangerous. But legal restrictions aren’t imminent.
Boise City Councilwoman Lauren McLean said she’s not ready to put an outright yew ban in place.
“Step one: Educate. Step two: Regulate,” McLean said. “I believe in my heart of hearts that this would never be intentional, so it’s a matter of getting the word out and making sure it doesn’t happen again as we see new development in the Foothills.”
The planning process is one tool the city can use to avoid yew planting in neighborhoods where deer, elk or other wildlife might wander. Most residential subdivisions don’t include landscaping plans that approve or prohibit certain types of plans, planning director Hal Simmons said. But the city could add a restriction on yews and other toxic plants to its list of standard conditions for any subdivision in the Foothills or along the Boise River.
“Any time we can cooperate, we’re having a better day,” McLean said. “But there’s a place for regulation. And, especially when plans come in front of me, I couldn’t look away if a yew were in the plans.”