Acer rubrum is a common shade and autumn accent tree in Eastern North America. Red Maple is characterized by bright red or yellow autumn color and valued for its relatively quick growth, dense shade, and symmetry in youth.
Alternate common name: Swamp Maple
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F E A T U R E S |
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Form
-large shade tree
-species form matures at about 70' tall x 40' wide; the many cultivars are smaller
-upright oval to upright rounded growth habit in youth
-upright rounded growth habit for most mature cultivars
-medium growth rate |
Foliage
-opposite arrangement; blades have medium green uppersides and light green to silvery undersides; these are noticeable on windy days
-3- or 5-lobed, the basal 2 (if present) much smaller than the upper 3, with each of the lobes serrated and sometimes lightly incised
-the blades are about 3" long x 3" wide, but there is great variability in leaf shape
-distinct palmate venation
-autumn color of the species ranges from bright yellow to orange to red (most cultivars have outstanding autumn color in various shades of red) |
Flowers
-globular to pendulous clusters of red inflorescences in late winter or early spring
-noticeable long before the foliage emerges, not especially showy, but somewhat ornamental since little else is flowering at this time of the year |
Fruit
-2 samaras per stalk, having semi-divergent (45 degree angle) wings, in pendulous clusters from the stems, maturing to red-brown in Oct., but often in reduced quantity or absent on many of the cultivars |
Twig
-red stems with off-white lenticels occur on mature first-year wood, with bright red buds in winter; twigs soon turn into smooth silvery-gray branches
-lower branches on mature trees are not nearly as pendulous with upturned ends as those of Silver Maple (Acer saccharinum), a closely related species with which Acer rubrum can naturally cross-hybridize |
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Trunk
-the young, gray to silver, smooth trunk and branches will fissure to a variable degree leading to exfoliating strips of dark gray or black bark with age |
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C U L T
U R E
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Culture
-full sun to partial sun (shade tolerant only in youth)
-prefers moist, acidic soils, but will tolerate wet soils or moderately dry soils from acidic to neutral pH
-alkaline soils (those with a pH above 7.5) usually cause leaf chlorosis and a weakly growing tree, especially among the cultivars, due to manganese deficiency
-prone to Verticillium wilt, leaf scorch and leaf chlorosis; several pests can also occur
-abundantly available, as B&B and in containers |
Hardiness
-zones 3 to 9
Origin
-native to Eastern North America
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U S A G E |
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Assets
-excellent autumn color
-fairly rapid establishment and shade
-generally wet site tolerant (but less so in an urban environment)
-silvery bark on some young cultivars
-generally has symmetrical branching in youth
Liabilities
-alkaline soil-induced chlorosis and weak growth
-shallow root system surfaces by mid-maturity
-somewhat prone to Verticillium wilt and leaf scorch |
Function
-shade, specimen, autumn accent, or wet site tree
-often inappropriately used as a street tree (it does not respond well to urban stresses, usually gets too large, and has surfacing roots even in youth)
Texture
-medium texture in foliage and when bare
-thick density in foliage but average when bare |
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S E L
E C T I 0 N S |
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Varieties
and Cultivars
- Search
OSU PlantFacts for additional plants in this species
Alternates
-medium- to large-sized shade trees (A. platanoides, A. saccharum, Fraxinus pennsylvanica, Gleditsia triacanthos, Tilia cordata, T. tomentosa, < i>Zelkova)
-excellent bright red autumn color in trees (Acer palmatum [green-foliaged, non-cutleaf, upright forms], Nyssa sylvatica, Oxydendrum arboreum, Quercus coccinea, etc.) or shrubs (Euonymus alatus, Rhus coppalina, Viburnum rufidulum, etc.) |