Acer platanoides × truncatum

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Credits

Dan Crowley (2020)

Recommended citation
Crowley, D. (2020), 'Acer platanoides × truncatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-platanoides-x-truncatum/). Accessed 2021-01-27.

Genus

  • Acer
  • Sect. Platanoidea

Other species in genus

Glossary

hybrid
Plant originating from the cross-fertilisation of genetically distinct individuals (e.g. two species or two subspecies).
variety
(var.) Taxonomic rank (varietas) grouping variants of a species with relatively minor differentiation in a few characters but occurring as recognisable populations. Often loosely used for rare minor variants more usefully ranked as forms.

References

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Credits

Dan Crowley (2020)

Recommended citation
Crowley, D. (2020), 'Acer platanoides × truncatum' from the website Trees and Shrubs Online (treesandshrubsonline.org/articles/acer/acer-platanoides-x-truncatum/). Accessed 2021-01-27.

A hybrid of cultivated origin making a deciduous tree to 12 m or more. Bark grey to brown, slightly fissured. Leaves, chartaceous, 10 × 10–12 cm, 5-lobed, the central lobe broad triangular and acuminate, or oblong with a pair of acuminate teeth in the apical half, base truncate, lobes apically acuminate, margins entire; petiole yellow, 8–14 cm long, exuding a milky sap when broken; autumn colour orange. Inflorescence similar to A. platanoides. Samaras with wings spreading at obtuse angles; nutlets flattened. (le Hardÿ de Beaulieu 2003). 

USDA Hardiness Zone 7-8

RHS Hardiness Rating H5

Conservation status Not evaluated (NE)

A hybrid between the European Acer platanoides and Asian A. truncatum, this cross appears to have been in cultivation since 1989, when two selections, ‘Keithsform’ and ‘Warrenred’ were introduced by J.F. Schmidt and Son of Oregon. These two selections each show greater influence of the different parents, with ‘Keithsform’ displaying heavier branching and larger leaves, closer to A. platanoides, and ‘Warrenred’ finer branched with smaller leaves, more akin to A. truncatum. Trees belonging to this hybrid may be found growing as A. truncatum, as was the case with a plant received by the Sir Harold Hillier Gardens, Hampshire, in 2007 (Edwards & Marshall 2019). The hybrid is however, invariably represented by named selections, which thus far, all appear to have been introduced by J.F. Schmidt and Son. The heat tolerance of A. truncatum and the unfussy growing requirements of both parents render this hybrid useful in a variety of situations.


'JFS-KW187'

Synonyms
Urban Sunset®

RHS Hardiness Rating: H7

A J.F. Schmidt and Son introduction, this selection is an upright form that develops a tidy canopy, thus lending itself to planting in urban environments (Schmidt 2019). It has deep red autumn colour (Dirr & Warren 2019).


'JFS-KW202'

Synonyms
Crimson Sunset™

RHS Hardiness Rating: H7

Another J.F. Schmidt introduction, this selection is notable for its deep purple foliage, recalling Acer platanoides ‘Crimson King’. Described as heat and drought tolerant, its rich coloration is retained all summer before turning paler in autumn. It has a strong, upright form, thus may be useful in urban environments (Schmidt 2019). It is likely the most cold hardy of the Acer platanoides × truncatum selections (Dirr & Warren 2019).


'JFS-KW249'

Synonyms
Ruby Sunset®

RHS Hardiness Rating: H7

Introduced by J.F. Schmidt and Son, this selection is closest to A. truncatum in stature, with glossy leaves that turn orange-red to bright red in autumn. (Dirr & Warren 2019; Schmidt 2019).


'Keithsform'

Synonyms
Norwegian Sunset™

RHS Hardiness Rating: H7

Introduced in 1989 by J.F. Schmidt and Son and reportedly commonly planted since then, ‘Keithsform’ has a neat form, glossy foliage and yellow to red autumn colour (Jacobson 1996; Schmidt 2019). It is represented in several North American collections including the Bartlett Tree Research Laboratories and Arboretum, the Dawes Arboretum, Ohio and the United States National Arboretum, Washington D.C. (American Public Gardens Association 2017).


'Warrenred'

Synonyms
Pacific Sunset™

RHS Hardiness Rating: H7

‘Warrenred’ was introduced in 1989 by J.F. Schmidt and Son, at the same time as ‘Keithsform’ (Jacobson 1996). Of the two, ‘Warrenred’ has superior autumn colour, though within the same range as ‘Keithsform’, while it also colours earlier (Jacobson 1996). Like ‘Keithsform’, ‘Warrenred’ is well represented in North American collections.