American yew is not planted often because it is toxic to humans and animals, but for those who do plant it, it can handle all our cold weather and it welcomes birds. As with all yews, American yew is toxic to humans and certain animals, including cattle, horses and dogs. American yew is not toxic to deer, however, and they love it
The only member of the Taxaceae family native to Minnesota, Taxus baccata subsp. canadensis Marshall is also called Canada yew and ground hemlock. Hardy to USDA Zone 4, this sprawling shrub prefers partial shade and moist, well-drained, slightly acid soils. Not surprisingly, it’s typically found in understories of northern hardwood and spruce and fir forests, from Manitoba to Tennessee.
Within Minnesota, American yew grows wild in the northern one-third of the state. Travel south along the St. Croix River and along the Mississippi River to Iowa and you may find it in cool, damp woods; ravines and wooded swamps; along riverbanks; and along the edges of bogs.
Shade Garden Shrub
Plants typically grow slowly to 3 to 6 feet tall, though they can be as tall as 10 feet. The branches extend from the plant’s base and upward along its height. In an undisturbed setting, you’re more likely to see a clonal mat of this shrub than a single yew because branches root where they touch the ground.
The smooth branches spread horizontally for two-thirds of their typically 6-foot length before curving upward. The branches look flat because the narrow, sharply pointed needles project laterally. Needles are half an inch to an inch long and dark green on their upper surface. The underside is lighter green but darker in the middle along its length, making the leaf look striped. The leaf’s midrib is elevated so subtly that the leaf looks flat and because the leaves basically are flat, you can’t roll them between your fingers.
In April or May, the shrub flowers with interesting male and female cone-like structures called strobili. Male and female flowers are separate structures, usually on different branches of the same plant but sometimes on separate plants. A flower later becomes a fleshy red berry (aril) about a half-inch in diameter that ripens July to September. The aril is open at the top, showing the single dark brown seed inside.
American yew grows relatively slowly and lives a long time, making it a good investment for homeowners who want a shade-tolerant planting that won’t outgrow its space quickly. It grows 6 to 12 inches annually, reaching maximum height in about 10 years. Bird-watchers also may enjoy the American yew because its arils attract ruffed grouse, pheasants, cedar waxwings, robins, starlings and thrushes. Once an aril is eaten, the exposed seed is eaten by hawfinches, greenfinches and great tits.
Deer, unfortunately, also find yew tasty, which is why you won’t find it in Prairie Restoration’s native plant catalog. “It’s heavily browsed by deer and is difficult to use in the landscape without it being decimated by our heavy deer populations,” explains Gene Schmidt, woody plant production manager/boreal natives for the company at its site in Cloquet.
The University of Minnesota-Duluth cages its yews in its Bagley Nature Area. In addition to caging, protect your yew from winter burn by planting it in moist, well-drained soil with northern or eastern exposure and partial to heavy shade.
American yew is toxic to humans and certain animals, including cattle, horses and dogs, among others. All parts of this plant are toxic to humans except the flesh of the arils, although the seed inside each aril is poisonous. Sometimes victims do not experience symptoms and if the poisoning goes undetected, death can occur within hours. Other victims may have an accelerated heart rate, muscle tremors, convulsions, difficulty breathing, impaired circulation and cardiac arrest.
Yew’s toxicity persists in plant material that has been cut, so keep people and animals who might be inclined to chew it away from cuttings.
Don’t be scared off by American yew’s toxicity. Many ornamental plants pose health risks if eaten, including the Japanese and English yews.
Plant it to Preserve It
Planting American yew in gardens may be useful as a preemptive step to help this species survive: It is listed as a Species of Special Concern in some areas of its range because of deer browsing, land-clearing and rising temperatures. That’s true in Wisconsin, although the Minnesota Department of Natural Resources doesn’t currently consider American yew to be endangered, threatened or of special concern.
This article by Janet Cass appeared in the September/October 2019 issue of Northern Gardener.