Canadian Yew

Taxus canadensis

Description & Overview

Canadian Yew is Wisconsin native evergreen commonly found as an understory inhabitant of late-successional forests throughout the mid to upper portion of the state. Soft, dark green needles adorn sprawling, irregular branches, displaying attractive reddish bark and a unique habit. This native conifer is a great indicator of cool, moist, and old-growth site conditions.

You may also know this plant as Canada Yew or American Yew.

Core Characteristics

Suggested Uses:

Canadian Yew is found in Wisconsin forests, slowly forming populations of ground-hugging clones by a process called layering. It is one of those rare evergreen, shade-loving groundcovers indicative of cool, moist, old-growth conditions.

There are several challenges associated with planting Canadian Yew in the landscape. The first is its toxicity. The second is its slow growth rate. The third is the White-tailed Deer’s preference for browsing on Canadian Yew, which also compounds issue number two.

The ideal use for this plant may be in restoration or within woodlands as a means of maintaining a certain level of diversity. Canadian Yew does not respond well to disturbances of any kind so choosing a site well off the beaten path may be best.

Enjoying moist and shadier conditions, Canadian Yew is a good choice for stabilizing soils along streams, ponds, or bogs, where they have room to spread.

Wildlife Value:

All parts of Canadian Yew are toxic except the red aril (fruit). This toxicity affects horses, cattle, dogs, and cats.

White-tailed Deer is not affected by its toxicity and will eat it with wild abandon, as will moose.

Ruffed grouse, Cedar Waxwings, and robins eat the fruit and are the primary seed dispersers of the seeds.

Maintenance Tips:

This plant can be rather high maintenance in that it needs to be protected from deer browsing, fire, and pretty much any other disturbance. Deer and rabbit will feed on yews. If you plant it, put a cage on it!

They tend to sprawl and may not be a suitable choice for smaller areas, otherwise, continuous pruning may be required.

Pests/Problems:

Black Walnut Tolerant: Yes and No (somewhat tolerant)
Deer Resistant: No
Rabbit Resistant: No

Form and viability are naturally kept in check by local deer populations. In fact, due to its slow growth rate, Canadian Yew is intolerant of being browsed severely and the widespread decline of Canadian Yew in Wisconsin is likely in part due to the rise in the deer population.

Leaf Lore:

Interestingly, climate change threatens the range of Canadian Yew because it affects snow cover. Snow cover prevents Canadian Yew from being overgrazed in the winter months. Quite simply, if there is no snow cover then Canadian Yew will likely be overgrazed.

Canadian Yew are one of a few plants that can survive the deep shade of old-growth hemlock forests. Removal of hemlocks destroys the Canadian Yew beneath it. Truly, the removal of any over-story plant where Canadian Yew is found will lead to extirpation.

Several indigenous peoples used parts of the Canadian Yew for medicinal purposes. The Ojibwa used leaf decoctions to treat arthritis while the Menomonee steamed the needles and used them in herbal baths to ease rheumatism, numbness, and paralysis. The Potawatomi used a leaf decoction as a diuretic and a treatment for gonorrhea. The Algonquin boiled the needles with wild cherry to treat rheumatism and drank tea after childbirth to ‘bring out clots’ and alleviate pain.

The plant is typically monoecious, but, has exhibited dioecy. The size of the plant appears to influence sex expression. Small plants tend to be more male, but in the event it is monoecious there are more female strobili than male. Larger yews tend to be monoecious, but there are more male strobili than females on the plant.

In the 1960s, the United States Department of Agriculture and the National Cancer Institute began testing Canadian Yew for cancer-fighting chemicals. It was discovered that Paclitaxel, an active anti-cancer chemical, was present in the bark of Pacific Yew (Taxus brevifolia). Unfortunately, the demand for paclitaxel was greater than the supply of the plant and too difficult to produce synthetically. All yew species were then studied, leading to the discovery that Canadian Yew also contained paclitaxel as well as two other chemicals that could be used to synthesize paclitaxel. There is a theory that with such high levels of taxanes in Canadian Yew, the species has the potential to become one of the most valuable natural sources for the pharmaceutical industry.

Companion Plants:

Canadian Yew is commonly found amongst Jack Pine (Pinus banksiana), Balsam Fir (Abies balsamea), Pin Cherry (Prunus pensylvanica), Eastern White Pine (Pinus strobus), Canadian Hemlock (Tsuga canadensis), Sugar Maple (Acer saccharum), Mountain Maple (Acer spicatum), Striped Maple (Acer pensylvanicum), Leatherwood (Dirca palustris), Paper Birch (Betula papyrifera), and Black Cherry (Prunus serotine).

Other shade-tolerant plants that would work well alongside Canadian Yew include Ostrich Fern (Matteuccia struthiopteris), Canada Mayflower (Maianthemum canadense), Blue Cohosh (Caulophyllum thalictroides), Pennsylvania Sedge (Carex pensylvanica), Canada Wild Ginger (Asarum canadense), and Jack in the Pulpit (Arisaema triphyllum).

CANADIAN YEW BENCHCARD