Taxus brevifolia (Western Yew, Pacific Yew, Mountain Mahogany)


Michael's Opinion

When mature, the western yew takes on a hauntingly beautiful and asymmetrical form. Its drooping branches often become covered by hanging moss when found growing in its native location within the humid understory of west coast forests. When grown into the form of a tree, rather than a shrub, this sweeping form is held aloft by a deeply fluted and often knotted trunk. The thin peeling bark further adds to the plants ghostly aesthetics with its rich colouration of red-brown on the outer layer, moving into a deep, almost iridescent, red-purple inner bark. The gloomy attributes of T. brevifolia are balanced wonderfully with its flat, twisted foliage and vibrant coral – red arils bearing a deep blue-black seed. When grown in the form of a shrub, it is quite common for the drooping branches to take root and form yew trees, creating large mats of genetically identical yew. T. brevifolia is very slow growing, highly rot resistant, and extremely long lived. Some trees are thought to be over 2000 years old; however this is difficult to ascertain due to the tendency for the inside of the tree to succumb to heart-rot fungus, causing the trunk to become hollow, and the growth rings impossible to count.

Botanical Information

FamilyTaxaceae
GenusTaxus
Speciesbrevifolia
SynonymsTaxus baccata var. brevifolia
CategoryWoody
TypeTree (evergreen), Shrub (evergreen)
ReferencesFarrar, J. L. (1995). Trees in Canada. Ottawa: Fitzhenry & Whiteside. Pielou, E. C. (1988). The world of northern evergreens. Ithaca: Comstock Pub. Associates.
OriginT. brevifolia is native to, and can be found along, the west coast of North America. Its distribution ranges from the southernmost tip of Alaska to central California and covers the coast and cascade ranges. Canadian provinces within the distribution range are Alberta and British Columbia. American States within the distribution range are Alaska, California, Oregon, Washington, Idaho, and Montana.
Ethnobotanical Uses
Disclaimer
The ethnobotanical uses for all Taxus species are similar. Yews around the world are valued for their longevity, medicinal properties, and wood quality. T. brevifolia was used by various indigenous groups for applications such as bows, harpoons, fish clubs, dip-net frames, canoe paddles, beads, cutlery, dishes, ornate trinket boxes, tool handles, and medicine. In particular the people of the Chehalis nation brew a tea from the compressed leaves, and give it to the young and the elderly. This induces perspiration, and is intended to aid the removal of various ailments. A red paint can be created through a mixture of wood-chips and oil. The rot resistant wood is ideal material for fence posts. Taxol is a chemical found in T. brevifolia which is used treat ovarian and lung cancer. Recently it has been synthesized rather than harvested for both efficiency and to lessen environmental impact. The wood of T. brevifolia is still used today for lutes and other stringed instruments.

Details

USDA Hardiness Zone4-5
USDA Hardiness Ref.
Canadian Hardiness Zone3b
Canada Hardiness Ref.
RHS Hardiness ZoneH7
RHS Hardiness Ref.
Temperature (°C)-23
Temperature (°F)-10
Height5-15 (25)
Spread2-8 (height[x]2)
GrowthSlow
Flowering PeriodMay, June

Description and Growing Information

General DescriptionT. brevifolia is a very slow growing and long lived plant which will grow in the form of either a small tree or a shrub depending on environmental conditions. The irregular crown of this understory species holds branches which may reach the same length as that of the height of the entire tree. The fluted trunk ranges between 10 and 50 cm DBH. In very old specimens it is common for the rot resistant trunk to become hollow due to heart - rot fungus.
ID CharacteristicThere are 3-10 species of yew recognized in the world which are all very similar in that they have flat needles, green buds, and bear a singular seed in each fleshy aril. T. brevifolia can be distinguished from other yews by its elliptical seeds and comparatively short needles which gradually taper to a point. The foliage is also described as being more orderly than other yews due to the whorled foliage twisting into an orderly ranked position.
ShapeUsually found as a small tree; T. brevifolia may take the form of a shrub when grown in dense, moisture-rich conditions. It is not unusual for the low-hanging branches to take root in the soil next to its parent. Young trees tend to hold their branches firmly horizontal. Mature trees tend to have drooping branches in an open asymmetrical crown which has a vaguely conical form. The branches can be as long as the tree is tall, occasionally giving this tree a spread of twice its height.
LandscapeDue to its irregular form and reputation for scrubby growth, Taxus brevifolia is rarely chosen over other yews for landscaping purposes. This does not mean it is unsuitable; only that fewer people see and desire its unconventional beauty. Being an evergreen, the foliage of the western yew provides greenery in the winter when the garden may otherwise be bare. The fluted trunk, with its variety of purple-red colourations and peeling bark, is another sensory treat. In an urban environment the incredible shade tolerance exhibited by T. brevifolia makes it a good candidate for planting near walls, fences, or any other small and shady location which could benefit from the inclusion of greenery. If desired it could be utilized as a hedge or topiary, however there are a plethora of cultivars and other species which would better fill that niche. In its native range, T. brevifolia plays an important ecological role by providing winter food to cervids such as black tailed deer, elk, moose, and caribou. Birds such as the waxwing, nuthatch, and blackbird rely on this food source as well.
PropagationT. brevifolia may be propagated either by seed or vegetative cuttings. Cuttings are best selected from terminal shoots in the late summer and may take up to 90 days to root. One can allow the lower branches to root in the soil around its parent and harvest this rooted branch for the creation of an entirely new tree. Both cold and warm stratification are required for T. brevifolia to be propagated by seed. Cold stratification is effective when temperatures reach 0 °C and must be maintained at that temperature for 90 days. A 90 day period of relative warmth is required after the cold stratification for germination. In its native habitat, birds which feed on the aril are responsible for dispersing the seed.
CultivationT. brevifolia tolerates a wide variety of conditions. It is best grown in fertile, moist soil which also has excellent drainage. As an understory species; T. brevifolia is extremely shade tolerant, but sensitive to damage from the sun, heat, and wind. Very old yews have been known to thrive in the open when the canopy above it has been removed. T. brevifolia can grow at a variety of elevations but prefers depressions which are abundant in moisture.
PestsT. brevifolia is quite resistant to pests and disease. Some insect pests which occasionally cause damage are the yew bug mite, strawberry root weevil, black vine weevil, and Taxus mealy bug. T. brevifolia often succumbs to heart-rot; however this does not appear to inhibit the already slow growth of older specimens.
Notable SpecimensThe largest known pacific yew can be found in the bottom of Hell's Canyon in Idaho. The tree is 8.5 m tall and has a DBH of 84.8 cm.
HabitatThe pacific yew has a limited range along the west coast. It can be found growing at a variety of elevations and is mainly found along stream beds and other corridors of water. It grows best in damp and humid atmospheres, and shares a forest with western larch (Larix occidentalis), grand fir (Abies grandis), Oregon white oak (Quercus garryana), red alder (Alnus rubra), and black cottonwood (Populus trichocarpa). T. brevifolia can be grown in rather dry locations as well.
Bark/Stem DescriptionThe young bark is smooth and has a red-brown colouration.As the tree ages the bark become progressively platier and begins to peel. The colour also deepens and mature trees have rich, deep, hues of purple, red and brown. The outer bark displays more of the brown colours while the inner bark displays more of the purple hues.
Flower/Leaf Bud DescriptionFoliage buds are inconspicuous and neither the flower or foliage buds provide ornamental value. Buds are a dull green colour, elliptical, and protected by many rounded scales. Approximately 1.5 mm diameter.
Leaf DescriptionThe mucronate needle foliage is approximately 1-3 cm long and 2-4 mm wide and has a green-yellow colouration. T. brevifolia has the shortest needles of yew found in North America, hence its name brevifolia (short-leaved). They are non glaucus and have a paler underside which is marked by white stomatal bands and a strong mid rib. The leaves are whorled on the branch but grow in a ranked formation. Petioles are approximately 1 mm in length.
Flower DescriptionT. brevifolia is usually a dioecious plant; however hermaphroditic plants may be found. Flowers may be observed between May and June. The pollen bearing male cones are a muted gold-yellow and are present in clusters on the underside of branches. 6-12 stamen each hold between 5 and 9 anthers. The Female cones are also found on the underside of branches but are borne singularly as opposed to the male clusters and occur less frequently. Pollen is dispersed to the female cone by wind transfer. Cones are 2-5 mm in diameter
Fruit DescriptionThe fruit of T. brevifolia is one of its most distinguishable characteristics. In a coral-red gelatinous cupped fruit called an arial; a single blue-black seed is held. The fruits are only borne on female plants and are the only part of the plant which does not contain the poison taxine. The aril with it's seed inside in approximately 1 cm in diameter. The seeds are ripe for dispersal between August and October.
Colour DescriptionT. brevifolia has yellow-green foliage, pale green buds, and the new growth is also pale green. There are a variety of colours present in the bark. The bark is a mosaic of rich browns, reds, and purples. The arils are bright coral-red and hold a single shiny, blue-black seed.
Texture DescriptionThe leaves of T. brevifolia tend to have a waxy texture; this is maintained into the young twigs. Young bark of T. brevifolia is rather smooth while older bark develops a characteristic shagginess. The seed is hard and smooth while the aril which covers it is firm and fleshy. When the aril is split, a slippery translucent yellow liquid can be found.

Photographs