The species of Taxus are more geographically than morphologically separable; and they were all treated by Pilger (1903) as subspecies of Taxus baccata. All species are poisonous; most contain the anti-cancer agent taxol; and a study of heartwood constituents of Taxus baccata, Taxus brevifolia, Taxus cuspidata and Taxus floridana found them to be chemically almost identical. However, the vast ecological amplitude displayed by the various described species (over 60° of latitude and an impressive temperature and precipitation range) suggests that they are, in a meaningful sense, true species. Detailed study of the genus (not neglecting the cultivated representatives), including extensive fieldwork, is much needed and long overdue[].

Common Name: Canadian Yew

General Information

Taxus canadensis is usually a shrub of spreading habit, often low and straggling; it can grow 120 - 180cm tall[].
The plant is harvested from the wild for local use as a food and a medicine. It is sometimes grown as an ornamental.
Taxus canadensis has an extensive range in northeastern North America. Although it has undergone a decline within that range over the last century, especially in the south, the extent of decline is currently insufficient for it to qualify for listing under any threatened category. The decline is expected to continue and may increase if predicted climate change impacts such as reduced snow cover lead to an increase in browsing pressures, the primary threat. A reassessment within the next ten years will be necessary. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

All parts of the plant, except the flesh of the fruit (actually an aril), are potentially highly poisonous. They contain the alkaloid taxine and , if ingested, can cause nervousness, trembling, slow pulse, pupil dilation, difficult breathing, abdominal pain, vomiting, diarrhoea, weakness and convulsions - in larger doses it can be fatal, having a paralyzing affect on the heart[, , , , , , ].

Botanical References

, ,

Range

N. America - Manitoba to Newfoundland, south to Iowa, Illinois, Tennessee and Virginia

Habitat

An understory shrub in rich forests (deciduous, mixed, or coniferous), bogs, swamps, gorges, ravine slopes, and rocky banks; at elevations from sea level to 1,500 metres[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Tree
Height	1.50 m
Growth Rate	Slow
Pollinators	Wind
Cultivation Status	Ornamental, Wild

Cultivation Details

Taxus canadensis is the most cold-hardy member of the genus - dormant plants can tolerate very heavy frosts with temperatures falling to between -34.3°c and -28.9°c[, ]. The young growth in spring, however, can be damaged by a few degrees of frost[].
Plants are very shade tolerant[], though can also succeed in full sun. Thrives in almost any soil, acid or alkaline, as long as it is well-drained[]. Grows in the wild on podzols, optimally well-drained slightly acidic silt loams, but the species also occurs near bogs[]. Plants grow best in a position sheltered from cold, dry winds[].
The plants produce very little fibrous root and should be planted in their final positions when still small[].
Plants in this genus are notably resistant to honey fungus[].
This species can form quite large clonal colonies of up to several hectares as a result of layering of branches[].
The plant is highly intolerant of disturbance, being readily extirpated by fire or if the forest in which it grows is logged[].
A dioecious species, both male and female forms must be grown if fruit and seed are required. Other reports say that this species usually has monoecious flowers (separate male and female flowers, but both are borne on the same plant)[, ].
Usually occurs as a low straggling understorey shrub in broadleafed and coniferous forests. Branches often layer so that quite extensive clumps can be formed. Sexual reproduction is rare[, ].

Edible Uses

Fruit - raw[, , , ]. Very sweet and gelatinous, most people find it delicious though some find it sickly[]. The fruit is a fleshy berry about 8mm in diameter and containing a single seed[]. 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

The Canadian yew is a very poisonous plant, though it was employed medicinally by several native North American tribes who used minute amounts of the leaves both internally and externally in order to treat a variety of complaints including rheumatism, fevers, influenza, expelling afterbirth and dispelling clots[, , ].
Modern research has shown that the bark and leaves contain the substance 'taxol'. Taxol has shown exciting potential as an anti-cancer drug, particularly in the treatment of ovarian cancers[, ]. This remedy is very toxic and, even when used externally, should only be used under the supervision of a qualified practitioner[]. See also the notes above on toxicity.

The plant is abortifacient, analgesic, antirheumatic, antitumor, diaphoretic, diuretic, emmenagogue, febrifuge and pectoral[].

Other Uses

The bark of most, if not all species of taxus is a moderate source of tannins[, ]. It is used in several species to produce a red dye[].

A green dye can be obtained from the leaves[].

Propagation

Seed - can be very slow to germinate, often taking 2 or more years[, ]. It is best sown as soon as it is ripe in the autumn when it should germinate 18 months later. Stored seed may take 2 years or more to germinate. 4 months warm followed by 4 months cold stratification may help reduce the germination time[]. Harvesting the seed 'green' (when fully developed but before it has dried on the plant) and then sowing it immediately has not been found to reduce the germination time because the inhibiting factors develop too early[]. Prick out the seedlings into individual pots once they are large enough to handle and grow them on in pots in a cold frame. The seedlings are very slow-growing and will probably require at least 2 years of pot cultivation before being large enough to plant out. Any planting out is best done in late spring or early summer, after the last expected frosts[].
Cuttings of half-ripe terminal shoots, 5 - 8cm long, July/August in a shaded frame. Should root by late September but leave them in the frame over winter and plant out in late spring[]. High percentage[].
Cuttings of ripe terminal shoots, taken in winter after a hard frost, in a shaded frame[].
Layering