Pacific Yew

Taxus brevifolia

Physical Characteristics

Taxus brevifolia is an evergreen Tree growing to 15 m (49ft 3in) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 6 and is not frost tender. It is in leaf all year, in flower from March to May, and the seeds ripen from September to November. The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Wind. The plant is not self-fertile. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid and very alkaline soils. It can grow in full shade (deep woodland) semi-shade (light woodland) or no shade. It prefers dry or moist soil. The plant can tolerates strong winds but not maritime exposure. It can tolerate atmospheric pollution.

Distribution

Western N. America - Alaska to California.

Habitats

Woodland Garden Secondary; Sunny Edge; Dappled Shade; Shady Edge; not Deep Shade;

Edible Uses

Edible Parts: Fruit Edible Uses: Fruit - raw[105, 161, 257]. Very sweet and gelatinous, most people find it delicious though some find it sickly[K]. The fruit is a fleshy berry about 8mm in diameter and containing a single seed[200]. Trees usually produce good crops every year[229]. All other parts of this plant, including the seed, are highly poisonous. When eating the fruit you should spit out the large seed found in the fruit's centre. Should you swallow the whole seed it will just pass straight through you without harm, if the seed has been bitten into, however, it could cause some problems.

Medicinal Uses

Cancer Diaphoretic Pectoral Poultice The Pacific yew is a highly toxic plant but it was employed medicinally by several native North American Indian tribes who used it to treat a variety of complaints[257]. Modern research has shown that it contains the substance 'taxol' in its shoots and bark. Taxol has shown exciting potential as an anti-cancer drug, particularly in the treatment of ovarian cancers[238]. Unfortunately, the concentrations of taxol are rather low and the bark of 6 trees is required to provide enough taxol to treat one patient[238]. This remedy is very toxic and, even when used externally, should only be used under the supervision of a qualified practitioner[238]. See also the notes above on toxicity. All parts of the plant, except the fleshy fruit, are diaphoretic and pectoral[257]. A decoction of the branches and leaves has been used in the treatment of lung problems[257]. An infusion of the crushed leaves has been used externally as a wash to cause perspiration and effect a general improvement in the health[257]. A poultice of the crushed leaves has been applied to wounds[257]. A decoction of small woody pieces has been used in the treatment of internal complaints including stomach pains and blood in the urine[257]. The leaves are harvested in early autumn or spring, the bark from autumn to spring, for commercial extraction of taxol[238]. Ingestion of 50-100g of needles can cause death.

Known Hazards

All parts of the plant, except the flesh of the fruit, are highly poisonous[1, 4, 7, 10, 19, 65]. Another report says that the toxic alkaloid found in other yews, known as taxine, is not found in this species and that the toxicity of this species has not been conclusively proven[270]. Poisoning symptoms are dry mouth, vomiting, vertigo, abdominal pain, dyspnoea, arrhythmias, hypotension & unconsciousness.