Acer saccharum Marsh.

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Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Article from New Trees by John Grimshaw & Ross Bayton

Recommended citation
'Acer saccharum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-saccharum/). Accessed 2024-03-18.

Genus

  • Acer
  • Sect. Acer, Ser. Saccharodendron

Common Names

  • Sugar Maple

Synonyms

  • A. saccharinum Wangenh., not L.

Other taxa in genus

Glossary

lobe
Division of a leaf or other object. lobed Bearing lobes.
acute
Sharply pointed.
appressed
Lying flat against an object.
divergent
Spreading from the centre.
glabrous
Lacking hairs smooth. glabrescent Becoming hairless.
glaucous
Grey-blue often from superficial layer of wax (bloom).
key
(of fruit) Vernacular English term for winged samaras (as in e.g. Acer Fraxinus Ulmus)
lobe
Division of a leaf or other object. lobed Bearing lobes.
palmate
Roughly hand-shaped; (of a leaf) divided partially or fully to the base with all the leaflets arising from the tip of the petiole (as in e.g. Aesculus).
pubescent
Covered in hairs.
subspecies
(subsp.) Taxonomic rank for a group of organisms showing the principal characters of a species but with significant definable morphological differentiation. A subspecies occurs in populations that can occupy a distinct geographical range or habitat.

Credits

Article from Bean's Trees and Shrubs Hardy in the British Isles

Article from New Trees by John Grimshaw & Ross Bayton

Recommended citation
'Acer saccharum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-saccharum/). Accessed 2024-03-18.

A deciduous tree to 30 m. Bark dark grey to greyish brown, fissuring, sometimes deeply so, with age. Branchlets slender, smooth, greenish, turning orange to reddish brown with age. Buds 0.6–1.2 cm long, acute, slightly pubescent, with four to eight pairs of imbricate scales. Leaves broadly pentagonal in outline, base cordate to truncate, three to five lobed, 7.5–15 × 20–24 cm, lobes apically acute or acuminate, margins remotely dentate with acuminate teeth, upper surface bright green, lower surface paler, glabrous, or with tufts in vein axils; petiole 4–8 cm long, green, glabrous, often grooved, broadest at base; autumn colours yellow to deep red or scarlet. Inflorescence terminal or axillary, corymbose, pendulous. Flowers yellow, 5-merous, pedicels long and slender, sepals obtuse, greenish yellow, pubescent on the outer surface, petals absent, stamens seven or eight, inserted in the middle of the nectar disc. Samaras 3 to 3.5 cm long, wings spreading acutely. Nutlets rounded. Flowering April to May, before or with unfolding leaves, fruiting in October (Rehder 1927–1940; Sargent 1965; Elias 1980​​​​; van Gelderen et al. 1994).

Distribution  Canada New Brunswick, Ontario, Québec United States Connecticut, Georgia, Illinois, Indiana, Iowa, Kansas, Kentucky, Maine, Maryland, Massachusetts, Minnesota, Missouri, New Hampshire, New York, North Dakota, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin

Habitat Lowlands on mixed soils (but not swamps), thriving on deep, rich, well-drained soils. A key component of eastern deciduous forest, associated species include Betula alleghaniensis, Fagus grandifolia, Prunus serotina, Quercus alba, Quercus rubra and Tsuga canadensis.

USDA Hardiness Zone 3

RHS Hardiness Rating H7

Conservation status Least concern (LC)

WORK IN PROGRESS: BEAN TEXT FOLLOWS

(Perkins et al. 2022)

A deciduous tree over 100 ft high in a wild state, with a trunk 9 to 12 ft in girth, forming a shapely rounded head of branches; branchlets glabrous. Leaves palmate, usually five-lobed, heart-shaped at the base, 4 to 6 in. wide; always downy in the axils of the chief veins beneath, but varying in different trees from glabrous to downy in other parts. Flowers without petals, greenish yellow, produced in clusters, each flower on a thread-like, hairy stalk more than 2 in. long. Fruit glabrous, wings 1 in. long, 38 in. wide.

Native of eastern N. America; introduced, according to Aiton, in 1735, but not many fine specimens are to be found in this country. The most notable arc in the Westonbirt collection, the finest there, and perhaps in the country, being in the Park, near the lodge, measuring 80 × 8 ft (1966). Others at Westonbirt are: Willesley Drive 70 × 434 ft; Circular Drive 63 × 534 and 65 × 434 ft (1966). In the grounds of Blenheim Palace, Oxon., there is a tree of 64 × 514 ft (1965). In Ireland the best recorded is at Mount Usher, Co. Wicklow, Eire, 62 × 714 ft (1966). In leaf, the sugar maple, especially in its more glabrous form, bears some resemblance to the Norway maple; but the sap of the sugar maple is watery, not milky as in the other.

The famous maple sugar of N. America is obtained almost solely from the sap of this tree. The State of Massachusetts alone used to supply more than half a million pounds annually. It is obtained by tapping the trees and collecting the juice, which is afterwards evaporated. As an ornamental tree in England this maple never seems to have been a great success, and although it appears to be quite hardy, does not grow quickly when young. In streets, and isolated in the meadows of New England, it is magnificent, and forms one of the chief elements in the glorious colour effects of autumn there, its leaves dying off into various shades of orange, gold, scarlet, and crimson, each tree, according to Emerson, retaining year after year its particular shades.

From the Supplement (Vol. V)

specimens: Hackwood Park, Hants, 80 × 812 ft (1977); Belton Park, Lincs., 68 × 8 ft (1978); Blenheim Palace, Oxon., 62 × 614 ft (1978); Bulstrode Park, Oxon., 90 × 11 ft (1967); Westonbirt, Glos., Willesley Drive, 88 × 512 ft, Broad Drive (NW), 82 × 534 ft (1982); Stratford Park, Glos., 60 × 512 ft (1984); Eastnor Castle, Heref., 50 × 712 ft and 52 × 714 ft (1977); Whiteways, Devon, 79 × 612 ft (1978); Pencarrow, Cornwall, 66 × 4 ft (1978); Mount Usher, Co. Wicklow, Eire, 70 × 734 ft (1975).

The three related species mentioned on page 232 have all been given the rank of subspecies of A. saccharum by Y. Desmarais in Brittonia, Vol. 7, pp. 347–87 (1952), A. barbatum as A. s. subsp. floridanum. The key character he uses to separate A. nigrum (A. s. subsp. nigrum) is that its leaves are yellowish green beneath and usually pubescent with short erect hairs, against glaucous or whitish and usually glabrous beneath in typical A. saccharum. See also E. Murray in Kalmia, Vol.7, pp. 13–19 (1975).

The example of A. nigrum in the Edinburgh Botanic Garden measures 62 × 414 ft (1985).

From New Trees

Acer saccharum Marshall

(Sect. Acer, Ser. Saccharodendron)

Sugar Maple

This species was described by Bean (B231, S60) and Krüssmann (K104), and is an important maple in temperate tree collections and landscapes. Authorities recognise variable numbers of subspecific taxa. Desmarais (1952) constructed a key to six subspecies, though additional taxa are recognised by van Gelderen et al. (1994). Presented below is a key to seven subspecies (devised by Peter Gregory and used with his kind permission), with an indication of the distribution of each from van Gelderen et al. (1994). However, the delimitation of the various subspecies and varieties is complex, as morphological characters vary continuously across the vast range. Most of the A. saccharum subspecies are well known in cultivation, and were described by Bean (1976a) under different names (A. barbatum, A. grandidentatum, A. leucoderme, A. nigrum). Material from the southernmost population, recognised as subsp. skutchii, is new to cultivation and is described below.

Numerous cultivars of A. saccharum have been named, with varying characters useful for different sites and conditions. A summary guide is provided by Dirr (1998).

1a.Leaf underside pale green to glaucous2
1b.Leaf underside yellow-green, lobes shallow, central lobe with divergent margins6
2a.Leaves large (≥ 10–15 cm)3
2b.Leaves small (5–10 cm)5
3a.Leaves deeply lobed, margins of central lobe parallel to inwardly angled4
3b.Leaves shallowly lobed, margins of central lobe slightly divergent; USA (Illinois, Indiana, Missouri)subsp. schneckii
4a.Lobe tips acute, leaf undersides glabrous to pubescent with silky appressed hairs; widespread in eastern North America (Canada, Mexico, USA)subsp. saccharum
4b.Lobe tips bluntly pointed, leaf undersides pubescent and glaucous; Guatemala, Mexico (southern)subsp. skutchii
5a.Margins of central lobe parallel to slightly divergent, lobe tips bluntly pointed; Mexico, USA (Florida, Texas)subsp. floridanum (Chapman) Desmarais
5b.Margins of central lobe inwardly angled, lobe tips rounded; USA (Oklahoma and Texas to Arizona and Montana, especially Rocky Mts.)subsp. grandidentatum
6a.Leaves small (5–10 cm), undersides with soft appressed hairs, bark smooth, pale grey to chalky white; USA (Alabama, Arkansas, Florida, Georgia, Louisiana, N. Carolina, S. Carolina)subsp. leucoderme (Small) Desmarais
6b.Leaves large (≥ 10–15 cm), undersides with stiff, short, erect hairs, bark rough, dark grey-brown to black; Canada (Ontario, Quebec), USA (northeast, south to Kentucky, west to Michigan, Iowa, Kansas)subsp. nigrum

A barbatum Michx

This species, known as the southern sugar maple, takes the place of A. saccharum in the coastal plain, from Virginia to Texas. It makes a smaller tree with a paler bark; leaves smaller, to 3 in. wide, usually downy beneath; lobes with entire or undulate margins. The name A. floridanum Pax has also been used for this species. It is in cultivation at the Glasnevin Botanic Garden, where there is a tree 25 ft high.

A leucoderme Small

Synonyms
A. saccharum var. leucoderme (Small) Sarg

A small shrubby tree, rarely more than 25 ft high, with a pale grey or chalky white bark. It is closely allied to the sugar maple but comes from further south, being commonest, according to Sargent, in the more northern parts of Georgia and Alabama. Leaves three- or five-lobed, 2 to 3{1/2} in. long and wide, the lobes triangular, with usually two large teeth; the base truncate or slightly heart-shaped; lower surface covered with whitish velvety down, especially where the five veins meet the leaf-stalk, which is glabrous. Introduced to Kew in 1902, when seed was received from Prof. Sargent. The specimen now in the collection measures 28 × 1{3/4} ft (1960). There is one at Westonbirt, Glos., measuring 51 × 2{3/4} ft (1967).

A nigrum Michx. f.

Synonyms
A. saccharum var. nigrum (Michx. f.) Britt

Another close ally of the sugar maple, known as the black maple, and found growing with it in the northern states of eastern and central U.S.A. The marks of distinction are the darker, more furrowed bark, the darker and duller green leaves with rather drooping sides, and the shallower, more rounded toothing of the lobes. According to Sargent it may be distinguished at all seasons by the orange colour of the branchlets.


'Flax Mill Majesty'

Synonyms / alternative names
'Majesty'

RHS Hardiness Rating: H7

USDA Hardiness Zone: 3

Introduced by Flax Mill Nursery, New York in 1983, a large, vigourous and symetrically-growing form with dark green leaves that colour red to orange notably early (Jacobson 1996). Noted is as well suited to northern parts of the United States by Dirr & Warren (2019).


subsp. skutchii (Rehder) A.E. Murray

Subsp. skutchii forms a tree to 20 m tall. Branchlets glabrous. Leaves 12–16 × 14–20 cm, lower surface glaucous with dense tomentum on the veins. Samaras 2.5–4.5 cm long. Van Gelderen et al. 1994. Distribution GUATEMALA; MEXICO. Habitat Cloud forest over limestone. USDA Hardiness Zone 7–8. Conservation status Not evaluated. Illustration NT106.

This is the southernmost variant of the sugar maples, but its precise delimitation in the western Mexican mountains is not entirely clear (S. Hogan, pers. comm. 2007), as subspp. floridanum, grandidentatum and saccharum also penetrate Mexico (van Gelderen et al. 1994). Material from Tamaulipas in cultivation in the western United States appears to fit subsp. skutchii, and has large leathery leaves that persist into the New Year, when they colour red and fall slightly before or as the new leaves emerge, thus making the tree almost evergreen. At Tregrehan at least it has attractive pinkish spring growth (T. Hudson, pers. comm. 2007). There is a good specimen in the Hogan–Sanderson plantings in Northeast 11th Avenue, Portland, Oregon, and it is grown in the southeastern states from collections made by Yucca Do Nursery. It is rare in Europe, but a few examples are known. Tom Hudson (pers. comm. 2007) planted one in 1995 at Tregrehan but, in the belief that it was tender, put it in a sheltered site where competition from other trees has suppressed it, and it is still only 2 m in 2007. This taxon in fact appears to be extremely hardy, reported to tolerate at least –18 ºC, and to grow well in heavy clay soils (Raulston 1996), although leaves will be lost if temperatures fall below this (Hogan 2008).


'Temple's Upright'

A very striking form with a narrow columnar habit. Once known as A. saccharum monumentale.

var. rugelii (Pax) Rehd.

Synonyms
A. rugelii Pax

A large tree with thin, three-lobed leaves; the lobes usually entire, triangular, pointed; lower surface rather glaucous and downy. Found wild from N. Carolina and Georgia to Missouri, being the common form of sugar maple in that region. The lower branches often bear leaves identical with those of the type. Introduced to Kew in 1908.