The yew plants used for landscaping in the Treasure Valley are all poisonous to wildlife, people and dogs. 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. Here’s what you need to know to determine whether you have yew in your yard and how to cover or remove the plant:
NAME DOESN’T MATTER
Japanese yew (Taxus cuspidata) is the variety often attached to wildlife poisoning, but English/European yews (Taxus baccata), Chinese yews (several species) and Canadian yews (Taxus canadensis) also are poisonous. Japanese yew and its hybrid with English yew are the primary landscape yews in southern Idaho, said Lynn Kinter, the lead botanist at Idaho Fish and Game.
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The naming can get confusing. Dennis Fix, the owner of FarWest Landscape and Garden Center in Boise, said his store doesn’t have anything labeled “Japanese yew.” Instead, you’d find names like “Irish yew,” “upright yew” and “dark green spreader yew.”
“They’re all toxic,” Fix said.
HOW TOXIC IS IT?
Yew poisoning is lethal to people, large animals such as cattle, horses and elk and pets. Small amounts can prove fatal.
“The leaves are poisonous,” Kinter said. “The stems are poisonous. And the seed inside the berry is poisonous. ... As small of a contact as a dog chewing on a branch of one of these shrubs can cause the dog to die.”
Kinter has one yew in her yard.
“I’m going to take mine out,” she said. “Even though I’m not in what might be a dangerous part of town (for wildlife), I do have a dog that loves to chew on sticks.”
HOW TO IDENTIFY A YEW
Yews have flat, evergreen leaves or needles that are about an inch long, an eighth of an inch wide and pointed on the ends. The female plants have red, pea-sized berries in the summer and fall that have openings on the end, allowing you to see the brown seed inside. The most similar evergreens are hemlock and spruce but they have brown cones. Hemlock needles are rounded on the end and spruce needles are skinny and sharp. If in doubt, clip a branch and take it to a garden center or other expert.
IF YOU WANT TO KEEP IT
Wrap the yew with burlap for the winter and secure the burlap with landscape staples. Make sure you secure it well enough at the ground level to keep animals out. This process is easier if you prune the shrub first, Kinter said.
IF YOU WANT TO REMOVE IT
Cut the yew down and dig out the roots. If you don’t remove the roots, it will grow back. If you can’t get the stump out of the ground, an herbicide will kill the plant — but that takes time. When you remove the plant, be sure to dispose of it at a landfill. The dead branches remain poisonous, Kinter said.
IF YOU WANT TO REPLACE IT
Yews fill a niche for an evergreen that likes shady areas. Idaho native plants that could fill those spots, Kinter said, include: Western swordfern, Oregon boxleaf, curl-leaf mountain mahogany, russet buffaloberry, oakleaf sumac and Oregon grape-holly.
Idaho native plants that aren’t evergreens but like shade include syringa, Woods’ rose, thimbleberry, oceanspray, mallow ninebark, Rocky Mountain maple, golden currant, red flowering currant, common snowberry, red-twig dogwood and highbush cranberry/mooseberry.
Non-native evergreen options could include evergreen huckleberry, dwarf Alberta spruce, false cypress and arborvitae (attractive to deer).
DID YOU KNOW?
Yews were used for construction of longbows in European and Native American history and in the synthesis of the cancer drug Taxol. ... FarWest gets most of its yews from Oregon. The supplier sends “truck loads” of the plants to the East Coast each year, Fix said. ... As popular as yews are here, landscape architect Chuck Edwards of Breckon Land Design says he doesn’t use them because they don’t thrive. “I just never liked how they performed,” he said. “I’ve just seen so many of them die in commercial applications of other people’s designs. ... I don’t think it likes our soils and heat.”