Pacific yew (Taxus brevifolia) is an evergreen tree species native to the coastal regions of Western North America. Pacific yew has a history of usage by Native Americans, who regularly used the lumber to create bows and paddles. This tree grows very slowly and has an established pattern of rotting from the inside.
I. Appearance and Characteristics
Taxus brevifolia, the Pacific yew or western yew, is a species of tree in the yew family Taxaceae.
Pacific yew is native to the Pacific Northwest. It ranges from southernmost Alaska south to Northern California, mostly in the Pacific Coast Ranges, but with isolated disjunct populations in southeast British Columbia and in Northern Idaho. It grows in varying types of environments; however, in drier environments it is mostly limited to stream-side habitats, whereas in moist environments it will grow up onto slopes and ridgetops, at least as high in altitude as 1,400 meters (4,600 ft) above sea level.
Pacific yew is shade tolerant, but can also grow in the sun. The tree’s shade tolerance allows it to form an understory, which means that it can grow along streams providing shade to maintain water temperature.
A small evergreen conifer (sometimes appearing as a shrub), the Pacific yew grows to 10–15 meters (33–49 feet) tall and with a trunk up to 50 centimeters (20 inches) in diameter, rarely more. In some instances, trees with heights in excess of 20 m (66 ft) occur in parks and other protected areas, quite often in gullies. The tree is extremely slow growing, and has a habit of rotting from the inside, creating hollow forms. This makes it difficult and sometimes impossible to make accurate ring counts to determine a specimen’s true age.
Often damaged by succession of the forest, it usually ends up in a squat, multiple-leader form, able to grow new sprouts from decapitated stumps. In its shrub form, sometimes called “yew brush”, it can reproduce vegetatively by layering.
It has thin, scaly bark, red then purplish-brown, covering a thin layer of off-white sap wood with a darker heartwood that varies in color from brown to a purplish hue to deep red, or even bright orange when freshly cut. The leaves are lanceolate, flat, dark green, 1–3 cm (3⁄8–1+3⁄16 in) long and 2–3 millimeters (3⁄32–1⁄8 in) broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.
The seed cones are highly modified, each cone containing a single seed 4–7 mm (3⁄16–1⁄4 in) long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8–15 mm (5⁄16–9⁄16 in) long and wide and open at the end. The arils are mature 6–9 months after pollination. The seeds contained in the arils are eaten by thrushes and other birds, which disperse the hard seeds undamaged in their droppings; maturation of the arils is spread over 2–3 months, increasing the chances of successful seed dispersal.
The male cones are globose, 3–6 mm (1⁄8–1⁄4 in) diameter, and shed their pollen in early spring. It is mostly dioecious, but occasional individuals can be variably monoecious, or change sex with time.
Many parts of yews are poisonous and can be fatal if eaten, including the seed which should not even be chewed.
II. How to Grow and Care
Pacific yew requires particular attention to soil and moisture to ensure a thriving growth. The plant prefers well-drained, slightly acidic soil, accompanied by consistent moisture levels without being waterlogged. Special care points include sensitivity to transplantation and root disturbance, necessitating careful handling. Pacific yew’s dense foliage can also harbor fungal diseases, thus requiring vigilant monitoring and appropriate airflow. Overall, pacific yew presents a challenging care regimen for gardeners due to its specific soil and moisture needs coupled with its sensitivity to environmental changes.
Sunlight
Pacific yew thrives in partial sun, with dappled sunlight being most beneficial for optimal growth. It can tolerate full sun to full shade, but these conditions may present growth challenges. In intense sunlight, pacific yew may experience stress leading to scorched leaves, while full shade can result in leggier growth and reduced vigor. Ideally, pacific yew should be planted outdoors where it can receive filtered light, such as under the canopy of larger trees. This will mimic pacific yew’s natural understory habitat, enhancing its health and growth resilience. Adaptive traits like needle-like leaves help pacific yew manage light exposure efficiently.
Temperature
The pacific yew is a hardy plant and will thrive in temperatures around 20 ℃, as long as it does not become waterlogged. It can withstand temperatures as low as -5 ℃, but if the temperature drops below -25 ℃, the pacific yew will struggle to survive.
Watering
Originating from the moist, shaded understory of Pacific Northwest forests, pacific yew is accustomed to a consistent yet moderate water supply. This species thrives in environments with high humidity and demonstrates a notable resilience to occasional dry spells. Watering for pacific yew should be adjusted to once every 1-2 weeks, aligning with its natural habitat’s rhythm. Cultivated primarily outdoors due to its affinity for cooler climates and evergreen nature, pacific yew benefits significantly from mulching which helps retain soil moisture and mimics the forest floor’s conditions.
Soil
The pacific yew tolerates most soils and will happily grow in almost any soil that has a pH value between 5.6-8.5. However, it is sensitive to soil compaction, so well-draining soil is vital to keep your tree happy and healthy. The ideal soil for the pacific yew is slightly loamy with a high percentage of sand or clay granules.
Fertilizing
For pacific yew, a balanced nutrition fertilizer is suggested to ensure robust growth and health. Apply this quarterly, adjusting the rate according to package guidelines, usually a tablespoon per square foot of soil around pacific yew. The benefits include promoting root strength and potential fruit development. Be cautious to avoid over-fertilization, which can harm roots. Seasonal variation in growth may necessitate increased spring fertilization, tapering off in fall. For safety, water pacific yew after application to help soil absorb nutrients effectively.
Pruning
The pacific yew is very hardy when it comes to pruning, and, because of this, it is commonly used in creating topiary. The best time to prune is toward the beginning of spring or at the end of summer. If you choose to prune your pacific yew at the beginning of spring, then this will encourage faster growth, making it a popular option for younger plants. Don’t prune the top of your pacific yew unless it has already reached your desired height, as it is unlikely to regain its height very quickly. Prune your pacific yew once or twice a year by snipping a little on all sides until you have the desired shape. Wear gloves when pruning as most parts of the pacific yew are poisonous.
Propagation
Pacific yew is a slow-growing evergreen, known for its medicinal value and ornamental appeal. Propagation through cuttings is practical and maintains genetic fidelity. Semi-hardwood cuttings taken from healthy parent plants should be treated with rooting hormone and placed in a well-draining, sterile medium under high humidity. Maintaining constant moisture without waterlogging is crucial for root development. After rooting, gradual acclimatization to ambient conditions ensures successful transplantation.
Transplanting
The best time for transplanting pacific yew is when the weather is mild, typically in late spring through mid-summer, allowing roots to establish without extreme heat. Choose a shady location with well-drained soil. Water adequately after transplanting to encourage growth.
Repotting
Repot pacific yew biennially, during early spring to align with its growth cycle. As a slow-growing conifer, it needs a moderately-sized pot with ample drainage. Post-repotting, pacific yew prefers consistent moisture but not waterlogged soil, and partial shade to recover. Use a pot just a few inches larger to avoid overpotting, which can foster root rot.
III. Uses and Benefits
- Ornamental uses
Piny pacific yew is a striking tree that adds wildlife and ornamental value to gardens. Young versions make excellent shrub-like hedges, while mature specimens make interesting border trees along garden paths in informal and woodland gardens. Its evergreen foliage adds interest to any garden all year-round. Birds flock to this tree to eat the seeds and berries.
- Medicinal uses
The chemotherapy drug paclitaxel (taxol), used in breast, ovarian, and lung cancer treatment, can be derived from Taxus brevifolia and other species of yew. As it was already becoming scarce when its chemotherapeutic potential was realized around the 1990s, the Pacific yew was never commercially harvested from its habitat at a large scale; the widespread use of the paclitaxel was enabled circa 2003 when a semi-synthetic pathway was developed from extracts of cultivated yews of other species.
- Other uses
Traditionally, the resilient and rot-resistant wood was used by Native Americans to make tools, bows (backed with sinew), arrows, and canoe paddles. Other purposes for yew included making harpoons, fish hooks, wedges, clubs, spoons, drums, snowshoes, and arrowheads. The foliage and bark was used for medicinal purposes. Members of the Pit River Tribe would sell this plant to the Ukiah. The Concow tribe calls the tree yōl’-kō (Konkow language).
Modern-day longbow makers report that a very small percentage of yew trees are of a grain suitable for their craft. The Japanese have used the wood for decorative purposes, and the Taiwanese have valued it as well.
