A deciduous tree 90 to 120 ft high, with a trunk 9 to 12 ft in girth in America and reaching the lesser of these dimensions under cultivation in Central Europe. The habit is extremely graceful, the tree forming a huge spreading, rounded head with the smaller branches and branchlets pendulous; bark light grey; branchlets glabrous. Leaves five-lobed (the lobes sharp-pointed and irregularly toothed), heart-shaped at the base, 4 to 6 (occasionally 8) in. long, about the same in width, glabrous and light green on the upper surface, white and minutely downy beneath. Flowers greenish yellow, without petals, opening long in advance of the leaves and produced in short dense clusters from the joints of the previous year's wood. Fruit on slender, pendulous stalks 11⁄2 to 2 in. long, the wings round-ended, 1⁄2 to 3⁄4 in. wide, spreading at a broad angle.
Native of eastern N. America; introduced in 1725. This maple is the fastest-growing of the American species, and a tree of great beauty in habit and foliage. A little wind will set the long pendulous branches swaying, and by revealing the silvery under-surface of the leaves makes it one of the brightest of tree pictures. In mild seasons it will flower as early as the elm, and, perhaps in consequence, rarely develops seeds freely with us. In N. America the seeds are ripe by May, and falling to the ground, germinate at once and produce several pairs of leaves before autumn. In middle Europe it is more freely planted than in England, and is perhaps the most striking of all deciduous trees in N. Central Germany. Unfortunately, owing to the rather brittle nature of the wood, it is not suitable for use as a street tree, and may suffer damage when in leaf if grown in positions where it is subjected to gusty winds; in open parkland it seems to give less trouble in this respect. The leaves fade into yellow or red before falling.
Few deciduous trees of N. America have fared better in cultivation in the British Isles than the silver maple. The tallest at Kew grows by the Japanese Gate and measures 92 × 103⁄4 ft (1965), but this is surpassed by a tree at Westonbirt, in Willesley Drive, 100 × 8 ft (1965). There are two specimens about 70 ft high in the Pinetum at the R.H.S. Garden, Wisley.
Raised from seed, this maple produces many slightly different forms, several of which have received distinctive names. The following are the most important:
cv. 'Born's Graciosa'. – A new variety, raised by the firm of Georg Born, Rosenheim, Germany, and in commerce on the continent. Leaves lobed almost to the middle, the segments narrow, deeply toothed or lobed; said to be a graceful and vigorous tree.
cv. 'Crispum'. – A close-growing variety with the leaves deeply lobed and the margins crinkled. Of American origin.
f. laciniatum (Carr.) Rehd. – A group name applying generally to forms in which the leaves are divided into deeper and narrower lobes than in the type. It is founded on A. wagneri laciniatum, described in Rev. Hort., 1868, p. 387. “A. wagneri” is probably an error of wageri, from Sir Charles Wager, who introduced the silver maple. The best-known clone referable botanically to this group is 'Wieri' (q.v.).
cv. 'Lutescens'. – Leaves orange-yellow when young, later yellowish. Späth's nurseries, before 1883.
cv. 'Pendulum'. – Branches pendulous. The tree which Nicholson had in mind when publishing this name (Gard. Chron., Vol. 15, 1881) was distributed by Van Volxem's nurseries. It was in cultivation at Kew in his time but was removed many years ago.
cv. 'Pyramidale'. – A form of broadly columnar habit. Späth's nurseries, 1885.
cv. 'Wieri'. – Branches pendulous; leaf-lobes narrow and sharply toothed. Founded in 1873 by D. B. Wier and put into commerce originally by the American firm of Ellwanger and Barry.
From the Supplement (Vol. V)
specimens : Kew, Japanese Gateway, 88 × 123⁄4 ft (1982); Osterley Park, London, 98 × 103⁄4 ft and 90 × 111⁄2 ft (1982); Finsbury Park, London, 72 × 111⁄4 ft (1982); R.H.S. Garden, Wisley, Surrey, Pinetum, 97 × 8 ft and 94 × 71⁄2 ft (1980); Bradstone Brock, Surrey, 85 × 113⁄4 ft (1982); Westonbirt, Glos., Willesley Drive, 111 × 91⁄2 ft and 95 × 9 ft (1982); Sandford Park, Cheltenham, pl. 1925, 70 × 101⁄4 ft (1978); Henrietta Park, Bath, 70 × 103⁄4 ft (1981); Cotehele, Cornwall, 98 × 12 ft (1981). And to show the rate of growth when young: Chase Cottage, Haslemere, Surrey, pl. 1966, 66 × 41⁄4 ft (1986).
It has been suggested that the silver maple is subject to wind-breakage only in North America. This, sadly, is a fallacy, for there is ample evidence that not only mature trees may suffer in this way but even newly planted ones can be damaged. On the other hand, it does seem to be the case that some trees are more wind-tolerant than others – a matter worth investigating, since the silver maple is a beautiful, fast-growing tree. In the meantime, it is advisable to avoid planting it by thoroughfares or in public places, and to reject any nursery trees which have thick young growths.