Acer nigrum Michaux

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Credits

Dan Crowley (2024)

Recommended citation
Crowley, D. (2024), 'Acer nigrum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-nigrum/). Accessed 2024-06-20.

Genus

Common Names

  • Black Maple
  • Black Sugar Maple
  • Hard Maple

Synonyms

  • Acer barbatum var. nigrum (F.Michx.) Sarg.
  • Acer nigrum f. pubescens Deam
  • Acer nigrum f. villosum Deam
  • Acer saccharinum var. nigrum (F.Michx.) Torr. & A.Gray
  • Acer saccharophorum var. nigrum (F.Michx.) J.Rousseau
  • Acer saccharophorum f. palmeri (Sarg.) J.Rousseau
  • Acer saccharum var. nigrum (F.Michx.) Britton
  • Acer saccharum subsp. nigrum (Michaux) Desmarais
  • Acer saccharum var. palmeri (Sarg.) A.E.Murray
  • Saccharodendron nigrum (F.Michx.) Small

Other taxa in genus

Glossary

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

Dan Crowley (2024)

Recommended citation
Crowley, D. (2024), 'Acer nigrum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-nigrum/). Accessed 2024-06-20.

A deciduous tree to 25(–30) m. Bark grey when young, turning darker and fissuring longitudinally with age, forming narrow, irregular ridges. Branchlets stout, pubescent at first, orange to reddish-brown, becoming glabrous and grey. Buds ovoid, with five to nine pairs of imbricate, pubescent scales. Leaves broadly pentagonal in outline, base cordate to broadly cuneate, three to five lobed, 12–15 × 12–15 cm, lobes apically acute or acuminate, margins remotely dentate, upper surface dark green, lower surface paler, pubescent at least at first; petiole 7.5–12.5 cm long, often stout, green, glabrous or pubescent, often grooved, broadest at base, with leafy stipules; autumn colours yellow. Inflorescence terminal or axillary, corymbose. Flowers yellowish, 5-merous, pedicels long and slender, sepals connate, petals absent, stamens six to eight, inserted in the middle of the nectar disc. Samaras 1.2 to 4 cm long, wings spreading at a broad or narrow angle. Nutlets rounded or somewhat flattened. Flowering April or May, with unfolding leaves, fruiting in October. (Rehder 1927–1940; Elias 1980; van Gelderen et al. 1994).

Distribution  Canada Ontario, Québec. United States Arkansas, Connecticut, Kansas, Kentucky, Illinois, Indiana, Iowa, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin.

Habitat Lowlands, near streams and rivers, usually below 750 m asl, but sometimes up to 1600 m asl. Associated species include Acer saccharum, A. rubrum, Betula alleghaniensis, Fagus grandifolia and Quercus alba.

USDA Hardiness Zone 3

RHS Hardiness Rating H7

Conservation status Least concern (LC)

Taxonomic note Acer nigrum belongs to the sugar maple complex centred around A. saccharum. It is often treated as a subspecies of A. saccharum but we treat it and several of its relatives at species rank here. See the taxonomic note for A. saccharum for further discussion.

Closely allied to Acer saccharum within the sugar maple complex, A. nigrum is valued next to that species for syrup production, and the timber of the two is considered indistinguishable; both are referred to as hard maple in the trade (Grimm 2002). In terms of distinguishing the two in the field, A. nigrum is often distinguished from A. saccharum by its drooping leaves. While this character can be useful, it is not always reliable, and should only be used in combination with other characters. The bark of A. nigrum is more deeply fissured and darker, to which the Black Maple moniker refers. Shoots of A. nigrum are generally stouter than those of A. Saccharum, but a clear distinction between the two, at least early in the season, are the stipulate leaves of A. nigrum. Indeed, this character separates A. nigrum from all other maples. Sargent (in Bean 1976) notes the orange-coloured branchlets as a useful character for distinguishing the A. nigrum from A. saccharum all year round, though this character is also somewhat variable. Reported hybrids naturally have characters intermediate between the two species.

Horticulturally, Acer nigrum attains equal stature to A. saccharum and is considered the more heat and drought tolerant of the two (Kurz 2003; Dirr & Warren 2019). It is shade tolerant, slower growing and also long-lived (Kurz 2003), and though it tends to lack reds in its autumn colour, is consistent none the less. It is however more susceptible to leaf tatter than the best A. saccharum selections, and is less used than that species, as reflected in its fewer cultivars.

The tallest example recorded in the UK attained 22 m at Alexandra Park, Hastings, though it died in 1995 (The Tree Register 2022). The current champion is a tree at the Sir Harold Hillier Gardens which measured at 17.4 m in 2022, though individuals at the Royal Botanic Garden Edinburgh and in the garden of the Hare and Hounds, Westonbirt, were both 17 m in 2014 (The Tree Register 2022). The species has grown taller elsewhere in Europe, with a male tree at Rogów, Poland planted in 1958, standing 24 m tall with a diameter of 64 cm in 2023 (P. Banaszczak pers. comm. 2023).


'Greencolumn'

RHS Hardiness Rating: H7

USDA Hardiness Zone: 6a

Discovered in a wild population in Boone County, Indiana, by W.R. Heard in 1959, and introduced commercially in 1977–78 by J. Frank Schmidt & Son Co., Oregon (Jacobson 1996), Acer nigrum ‘Greencolumn’ has a broadly upright form, attaining 20 m, and unusually deeply furrowed bark (van Gelderen et al. 1994; Jacobson 1996). Its autumn colour is reliably good, turning shades of yellow and orange, and it is tolerant of heat and drought (van Gelderen et al. 1994; Jacobson 1996).


'Morgan'

RHS Hardiness Rating: H7

USDA Hardiness Zone: 4

A clone with outstanding orange to red autumn colour, selected by the Morton Arboretum (Jacobson 1996). Seemingly rare, it was described as ‘not yet in commerce’ by Jacobson (1996) and still does not appear to be comercially available. Cultivar names cannot be duplicated within a genus; it seems likely that the selection Acer × freemannii ‘Morgan’ predates this one, so this cultivar should be renamed.


'Slavin's Upright'

RHS Hardiness Rating: H7

USDA Hardiness Zone: 5

A broadly columnar tree with erect branching, Acer nigrum ‘Slavin’s Upright’ was selected in 1903 as a seedling growing near Salamanca, New York (Jacobson 1996). It was raised in Highland Park, Rochester, described in 1950 and named in 1955 for Bernard Henry Slavin, Superintendent of Rochester Parks (Jacobson 1996).