A favored poison from the 15th century that is now a common ornamental tree in western suburban neighborhoods is killing off desperate winter-stressed wildlife in Idaho. In fact, it has taken down antelope and elk so quickly that in certain cases they have been found dead with half chewed twigs still in their mouths. It’s no wonder some have dubbed it the “tree of death.”
Before the wildlife deaths in Idaho this winter, most guides to toxic plant toxicity claimed that deer, moose, antelope and elk were not affected by yew. However, deep snow and limited food sources have brought many desperate and food-stressed ungulates to the edge of towns and subdivisions where enticing—and surprisingly deadly—yew trees adorn the landscape.
Why Is It Deadly?
Japanese yew, a tree-like shrub that can grow 20 feet if protected from pruning shears, contains taxine A and B—deadly to humans, wildlife, horses, cattle, sheep, goats and dogs—even in small quantities. Whitetail deer, though, can consume it and walk away seemingly unscathed. Mule deer aren’t so lucky.
There’s really no warning for elk and other wild game. One minute they are munching on yew, then they wheeze a few times and die of poison-induced cardiac arrhythmia. Humans take a bit more time to succumb to it, taking around 30 minutes before yew poison causes heart failure. Two notoriously cunning women in 15th century Europe—Lucrezia Borgia and Catherine de Medici—used it to dispose of unwanted husbands and political opponents in part because it’s symptoms can be mistaken a heart attack. Ill effects can also include tremors, fever, difficulty breathing, dilated pupils and vomiting.
A number of other yew trees are at least somewhat toxic as well, including European yew (aka common yew), Chinese yew, and even natives such as Pacific, western and Canada yew. Japanese yew, though, contains the highest toxicity, and like its siblings, single plants can live upwards of 600 years.
How Many Animals Has It Affected?
During the winter of 2016-2017, this popular backyard plant took a heavy toll on elk and pronghorn herds that descended out of the high country following heavy snowfall into low-lying neighborhoods across Idaho. Desperate for a meal, seven elk died in the Boise Foothills, eight in North Fork and Challis, and another eight near Idaho Falls. In addition to those 23 elk deaths, 50 pronghorn met the same fate along the Idaho and Oregon border near Payette. Death by Japanese yew has even occurred as far east as Pennsylvania, where a mother black bear and three cubs died after snacking on this lethal shrub.
How Can You Identify Japanese Yew?
Identifying yew trees is relatively simple. Look for an evergreen with flat needles that are a darker green on the top than on the bottom, and are shorter than pine needles, ranging from less than an inch long to about an inch and a quarter. Yew needles grow on both sides of the stem and make a spiral down the branch. Its bark is often scaly and reddish-brown. Another key tell: if the tree in question has wide and round leaves, it’s not a yew. Yews are evergreens rather than deciduous, keeping their needles year-round. See Photos Below.Evergreen – Holds needles year-roundFlat needles – darker green on top than on bottomNeedles are less than an inch, to inch and a quarterNeedles grow on both sides of the stem and spiral down branchScaly, reddish-brown barkAlthough technically classified as a conifer, yews don’t produce cones, but female yews have berries that turn bright red in late summer and early fall. Each harbors a single poisonous seed, but oddly enough, the outside layer of the berry protecting the seed is the least poisonous part of the whole plant. Male yews, on the other hand, produce only flowers, which are also poisonous and look like miniature Brussel sprouts that angle downwards until the pollen is released in March and April and the flowers wither away.
Why Are Japanese Yew Still Legal?
With their gruesome capacity to inflict sudden death on so many species, one might wonder why yew trees are still prevalent today. Simply put: they are darn good looking. Yew’s pleasant aesthetics keep them as hot sellers at home and garden stores, often attracting buyers that don’t realize this popular ornamental shrub can be a such a killer. Yew is also frequently used during the holidays to make wreaths. It’s resilient ability to withstand harsh winters has also compounded its popularity.
How Do You Remove Japanese Yew?
Due to its robust nature, yew trees are hard to remove. Even if they die, their poison is not neutralized until the roots are pulled out. When considering Japanese yew, keep in mind that it is not native to the United States and is best avoided unless the location is absolutely isolated from the hungry mouths of wildlife. If you are removing, take care not to ingest any part of the plant. Burning the plants or wrapping them in burlap sacks will prevent them from being eaten by wildlife.Use the share links below to help spread the word about this dangerous plant.