A tree 70 to 100 ft high, with a trunk 6 to 10 ft in girth, and a head of often rounded form; bark reddish brown; young shoots bright grey, minutely hairy. Leaves very shortly stalked, 1⁄4 to 2⁄3 in. long, linear, but often broadest (1⁄16 to 1⁄12 in.) near the rounded base, tapering thence to a bluntish point, margins toothed, dark green above, with a clear, well-defined band of stomata each side of the midrib beneath. The leaves are mainly in two opposite, spreading ranks, but there are also smaller leaves on the upper side of the branchlet pointing forward, flattened to the branchlet, often inverted and showing the white-lined lower surface. Cones 1⁄2 to 7⁄8 in. long, oval, borne on a short downy stalk; the scales broadly obovate, about as wide as long, minutely downy except on the exposed part.
Native of eastern North America from Nova Scotia south-west to the region of the Great Lakes, south through the eastern States to Alabama and Georgia, but confined to the mountains in the southern part of its range; introduced early in the 18th century. This beautiful tree thrives very well in the moister parts of our islands, especially where the soil is good and retentive of moisture. There are good specimens in the west of England, and I have also seen excellent ones at Murthly, and elsewhere in Perthshire. The tree as grown in this country has a strong propensity to branch into several stems near the ground, and to form a large rounded head of branches very distinct from the slenderly tapered form of T. heterophylla. From that species it is also distinct in the usually (not invariably) tapered leaf, in the much more clearly defined, whiter lines beneath, and in the cones being shortly stalked (stalkless in T. heterophylla). Visitors to Boston, Mass., have an opportunity of conveniently inspecting a primaeval wood of hemlock, which covers one of the hills in the beautiful Arnold Arboretum near that city. Here they have formed clean straight trunks, one of which (it may not have been the largest) I found in 1910 to be over 9 ft in girth.
The eastern hemlock grows more slowly in Britain than its western ally, T. heterophylla, and good specimens with a single bole are rare, the best being in Shropshire: Walcot Hall, 70 × 12 ft and 80 × 113⁄4 ft (1975); Oakley Park, 72 × 131⁄2 ft(1971).
T. canadensis is lime-tolerant – more so than any other tsuga according to Messrs Hillier. For its use as a hedging plant see Donald Wyman, Trees for American Gardens, Ed. 2 (1965), pp. 458-9.
cv. ‘Albo-spica’. – Tips of the young shoots white. As usually seen in cultivation this is of compact habit and is quite striking when in full growth. According to van Ouden and Boom there may be more than one clone under this name.
cv. ‘Cole’ (‘Cole’s Prostrate’). – A ground-hugging plant, attaining a spread of about 3 ft. Found in the wild in New Hampshire in 1931 by H. R. Cole.
cv. ‘Everitt Golden’. – A slow-growing small tree of narrow habit and rugged outline. Young leaves golden-yellow, later yellowish green. Like ‘Cole’ this was originally found wild in New Hampshire. It is possible that plants now grown as ‘Aurea’ are this clone.
cv. ‘Fremdii’. – A compact small tree of pyramidal habit, but spreading when old. Leaves crowded, some pointing out of the general plane. Found among seedlings by the American nurseryman C. Fremd and distributed in Europe by P. Koster of Boskoop. An example at Westonbirt, Glos., pl. 1939, measures 34 × 23⁄4 ft (1967).
cv. ‘Hussii’. – A slow-growing dwarf of irregularly branched, rugged habit. Branchlets congested, with very short, dark green leaves. Found in the USA about 1900.
f. microphylla (Lindl.) Beissn. Abies canadensis microphylla Lindl. – Leaves shorter than normal. A common seed-bed variant. The plant named by Lindley was raised by Fisher and Holmes of Sheffield from American seed; it had minute leaves resembling those of Daboecia cantabrica.
f. minuta (Teuscher) Rehd. T. canadensis var. minuta Teuscher in New Fl. and Sylv., Vol. 7 (1935), pp. 274-5 and fig. lxxxix – A minute form found in the Green Mountains of Vermont in 1927. Despite its small size it was fertile and surrounded by seedlings of the same habit, many of which were dug up and distributed. A named clone of this form is ‘Jervis’, probably of independent origin.
cv. ‘Nana’. – Of low, spreading habit, to 2 or 3 ft high, more in width. Leaves closely set. This is probably the T. canadensis var. nana of Carriere (1855).
cv. ‘Prostrata’. – Described in the present work in Vol. III (1933), p. 482, as a perfectly prostrate plant, seen growing in the garden of Mr Renton of Branklyn, Perth, in 1931 (T. canadensis var. prostrata Bean). The origin of this plant was not stated.
cv. ‘Pendula’. – A name of uncertain application. Probably the plants now grown under this name are mostly ‘Sargentii Pendula’ or the other possibly distinct pendulous form mentioned under it. But the epithet pendula was also applied to trees with long pendulous ends to the branches (cf., A. D. Webster, Hardy Coniferous Trees (1896), p. 132.
cv. ‘Sargentii Pendula’. – A pendulously branched variant, lacking a leading stem and forming a beehive- or dome-shaped bush, but procumbent and wide-spreading if not trained up early in life. It was put into commerce by Samuel Parsons of Flushing, New York, in 1879 as Abies canadensis Sargenti pendula.
This hemlock is one of four found by General Howland in the Fishkill Mountains above the Hudson River in the late 1860s. One he kept for himself; the other three he gave to his neighbour Henry Winthrop Sargent, who in turn planted one in his arboretum at Wodenethe, giving one to his cousin by marriage H. H. Hunnewell of Wellesley, Mass., and the other to his young cousin Charles Sprague Sargent, the future Director of the Arnold Arboretum, who had taken charge of his father’s garden near Boston after his return from Europe in 1868 (see further below).
The name ‘Sargentii Pendula’ commemorates H. W. Sargent, from whom Parsons is known to have obtained propagating material (Stout, Journ. New York Bot. Gard., Vol. 40 (1939), pp. 153-166). Parsons evidently thought highly of this hemlock, for he wrote to The Garden in 1875 announcing it as a forthcoming novelty, and in 1887 sent a photograph to the same periodical, from which an engraving was made and published (Garden, Vol. 32 (1887), p. 363).
The plant given to C. S. Sargent was placed in the family garden at Holm Lea, Brookline, and by about 1923 had made a flat-topped bush 6 ft high and 23 ft across (E. H. Wilson, Gard. Chron., Vol. 75 (1924), p. 107 and fig. 43). The Holm Lea estate was broken up after Prof. Sargent’s death in 1927, but the plant still exists in a private garden. He gave an account of the four Howland hemlocks in Garden and Forest, Vol. 10 (1897), p. 491, and Kent’s description of var. sargentiana is taken from this article, where it appears to be the Holm Lea plant that Sargent describes (Veitch’s Manual of the Coniferae, Ed. 2, pp. 465 and 466). But Kent clearly intended that the epithet Sargentiana should commemorate H. W. Sargent, who distributed General Howland’s discoveries, and to use the cultivar name ‘Sargentiana’ for the Holm Lea plant would cause confusion. The name ‘Brookline’ has been proposed for it (H. J. Welch, Dwarf Conifers (1966), p. 323). General Howland’s own plant survives, and there is still a large specimen in the remains of H. W. Sargent’s once famous arboretum (Gard. Chron., Vol. 141 (1957), p. 188).
Although most plants in Europe are probably the true clone ‘Sargentii Pendula’, seedlings of it have also been distributed. Some cultivated plants are narrow-topped, with steeply pendulous branches, and it is possible that these are a different clone, of European origin.