Acer grandidentatum Nutt.

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Credits

Dan Crowley (2024)

Recommended citation
Crowley, D. (2024), 'Acer grandidentatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-grandidentatum/). Accessed 2024-05-29.

Genus

Common Names

  • Bigtooth Maple

Synonyms

  • Acer grandidentatum var. brachypterum Palmer
  • Acer saccharum var. grandidentatum Sudw.
  • Acer saccharum subsp. grandidentatum (Nutt.) Desmarais
  • Acer brachypterum Woot. & Standl.
  • Acer saccharum subsp. brachypterum (Woot.& Standl.) A.E. Murray

Other taxa in genus

Glossary

lobe
Division of a leaf or other object. lobed Bearing lobes.

Credits

Dan Crowley (2024)

Recommended citation
Crowley, D. (2024), 'Acer grandidentatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-grandidentatum/). Accessed 2024-05-29.

A deciduous shrub or tree to 15 m. Bark dark brown, becoming scaly with age. Branchlets slender, glabrous, bright red, turning reddish brown to grey with age. Buds minute, acute at the apex with five to nine pairs of pubescent, imbricate scales. Leaves broadly pentagonal in outline, base cordate to truncate, three- to five-lobed, 4–12 × 4–14 cm, lobes apically obtuse or rounded, margins remotely dentate to sub-lobed (usually entire in var. sinuosum) with obtuse teeth, upper surface dark green, glossy, lower surface paler, often pubescent; petiole 2.5–5 cm long, green to reddish, glabrous or tomentose, often grooved, broadest at base; autumn colours yellow to scarlet. Inflorescence terminal or axillary, corymbose. Flowers yellowish, 5-merous, pedicels long and slender, pubescent, sepals connate, sparsely pubescent with long, pale hairs, petals absent, stamens six to eight, inserted in the middle of the nectar disc. Samaras 1.1 to 2.5 cm long, wings spreading or erect. Nutlets rounded. Flowering March to May, with unfolding leaves, fruiting in May to October (Sargent 1965; Elias 1980; Vargas-Rodriguez et al. 2020).

Distribution  Mexico Chihuahua, Coahuila, Nuevo León, Sonora, Tamaulipas United States Arizona, Colorado, Idaho, New Mexico, Oklahoma, Texas, Utah, Wyoming

Habitat Moist sites including wet canyons and valleys, stream banks between 1200 m and 2800 m asl. Associated species include Abies concolor, Fraxinus velutina, Juglans major, Pinus ponderosa, Platanus wrightii, Pseudotsuga menziesii var. glauca and Quercus spp.

USDA Hardiness Zone 4

RHS Hardiness Rating H7

Conservation status Least concern (LC)

The westernmost representative of the sugar maple complex, Acer grandidentatum is a species of interior western North America, extending from the eastern Rockies east to Texas, where its var. sinuosum occurs. The species has also been suggested as a parent of the Caddo sugar maples of Oklahoma (though see the account for A. saccharum). While it varies in leaf size and coloration, in its typical form it is separated from other sugar maples by its usually multi-stemmed or shrubby form, leaves often somewhat leathery with rounded lobes, the central lobe more deeply cut and narrowest at its base (Grimshaw & Bayton 2009). Its epithet, grandidentatum, refers to the large teeth typical of the leaves.

As with other members of the sugar maple complex, the species is of greatest significance within its native range, and a number of cultivars are readily available in North America. Though slow growing, it is tolerant of drought, cold, rapid changes in temperature and drying winds, though will not succeed in overly wet conditions (Dirr & Warren 2019). The species is becoming more important in urban conditions in the southwestern United States where it is valued for its autumn colour, which compares to that of typical A. saccharum (Kuhns 2003), though varies within populations and in response to environmental conditions (Kuhns 2003; Dirr & Warren 2019). Relatively untroubled by pests and diseases, its overall toughness is appreciated by those attempting to grow trees in more challenging situations.

The first material grown in Britain is thought to have been that at RBG Kew received from Charles Sargent in 1885 (Bean 1976), of which a single plant remains. It is now present in several other specialist UK collections, with a plant from seed collected by Hugh Angus (NATEX 10) in the Big Bend National Park, Texas, proving slow growing at Westonbirt, standing at 2.5 m tall in January 2024 (pers. obs). At Rogów, Poland, it is also slow growing; one specimen here, of Cochise County, Arizona provenance, dating from 1979, was frozen to the ground during very cold winter 1986–87. Though it survived, it has since attained only about 2 m in height (P. Banaszczak pers. comm. 2023).


'JFS-NuMex 3'

Synonyms / alternative names
Acer grandidentatum MESA GLOW™

RHS Hardiness Rating: H7

USDA Hardiness Zone: 4

An upright selection with reliable red autumn colour, MESA GLOW™ was selected by Rolston St. Hilaire of New Mexico State University for drought tolerance and adaptability, from seedlings sourced from the mountains of New Mexico and western Texas (Dirr & Warren 2019). It has faster growth than typical Acer grandidentatum and is advocated for use on streets and in urban landscapes by Dirr & Warren (2019).


'Manzano'

RHS Hardiness Rating: H7

USDA Hardiness Zone: 4

A selection from the Manzano mountains of New Mexico, attaining around 10 m in height (Dirr & Warren 2019). Its leaves are larger than typical Acer grandidentatum, turn red to yellow in autumn, and have a tendency to marcescence (Hatch 2021–2022; Dirr & Warren 2019). Plants under this name are reputedly seedling raised, so its naming as a single cultivar is innacurate and a group should be established.


'Schmidt'

Synonyms / alternative names
Acer grandidentatum ROCKY MOUNTAIN GLOW™

RHS Hardiness Rating: H7

USDA Hardiness Zone: 6a

Introduced around 1900 by J. Frank Schmidt & Son Co., Oregon, noted for its bright red autumn colour (Jacobson 1996).


var. sinuosum (Rehder) Little

Common Names
Canyon Maple

Synonyms
Acer barbatum var. sinuosum Ashe
Acer grandidentatum var. brachypterum Palmer
Acer mexicanum Gray
Acer saccharum var. sinuosum (Rehder) Sargent
Acer sinuosum Rehder

Var. sinuosum differs from typical A. grandidentatum in its smaller leaves (3.5–9.5 × 3.5–12 cm), apically obtuse to rounded, with ‘broad shoulders’ and usually lacking lateral sub-lobes.

Distribution

  • Mexico – Coahuila, Nuevo Leon, Tamaulipas
  • United States – Arizona, New Mexico, Texas

The differentiating features of typical Acer grandidentatum var. sinuosum are provided above, though things become somewhat blurred in the east of the range, where Texas populations begin to resemble A. floridanum and there is a possibility of hybridisation between the two taxa (Vargas-Rodriguez et al. 2020). There is very little material of the variety in cultivation to allow for convenient study, and while it may offer little from a horticulutural perspective, its position and ecological significance in the context of the sugar maple complex should not be overlooked.