The oldest public wildflower garden in the United States
Acer rubrum L.
Early Spring flowering
Red Maple is a large deciduous tree with a narrow to rounded compact crown growing 60 to 90 feet high but usually much less, and to a diameter of 2-1/2 to 4 feet. It has showy flowers, seeds and fall color. It is usually the earliest native hardwood to flower in Spring.
The largest Red Maple in Minnesota is located in Pine County and measures 80 feet high, 50 foot crown spread, 95 inches in circumference, scoring 187.5 points. Whereas the National Champion (as of 2019), located in New Haven County CT measures 72 feet high, 68 foot crown spread, 276 inches in circumference and scores 365 points.
Bark is gray and thin when young (up to 7 or 8 inches of tree diameter) with some white blotches and becoming with age fissured into long scaly ridges.
Twigs are slender, hairless and reddish with small white lenticels and leaf scars in a V-shape. Older twigs are a grayish-white. The buds are usually blunt varying in color from green to reddish with several scales. The lateral buds appear to have a short stalk.
Leaves are opposite, simple, up to 4 inches long, palmate, with 3 shallow short-pointed lobes. There are usually a pair of smaller lobes near the base from which radiates 5 main veins. The lobe margins are wavy and shallowly but regularly toothed. Bases are rounded to heart-shaped. Leaves are dull green above, whitish and with fine hair under, on green to reddish stalks and turn red, orange or yellow in Autumn.
Flowers: The flowers are unisexual, that is separate male and female flowers, sometimes on the same tree (monoecious) and sometimes on separate trees (dioecious). The 1/4 inch flowers are reddish, sometimes yellow, and occur in dense clusters of separate sexes before the leaves appear in late winter or early spring. Each flower has 5 sepals forming the calyx. Male flowers (staminate) are not stalked and have scaly bracts, numerous stamens with long filaments with anthers that have a dark stripe. Female flowers (pistillate) have a style split into 2 parts from a 2-carpel ovary and develop stalks up to 2 inches long. Flower clusters appear on last years twigs and when sexes are on the same tree, they will be on different branches.
Fruit: Female flowers mature to a pair of one-seeded samaras (keys) each with a broad wing up to 1 inch long, that are paired at the top, red initially and turning reddish-brown. These mature in late spring to early summer and drop from the tree. They are wind dispersed. Trees can bear seed as early as 4 years of age, which is unusually early in the Maple species.
Habitat: In its native habitat Red Maple prefers moist fertile soils of riparian areas, woods, valleys and can do well in upland settings and ornamental landscapes. It has moderate shade tolerance and will tolerate water-logged soils. The root system has a tap root and lateral roots. This is one of the most widely distributed trees in North America. It's young shoots are a favorite of White-tailed deer but in late summer to fall the plant leaves are toxic to cattle. It will re-sprout from stumps.
Names: The genus, Acer, is the Latin word for 'maple'. The species name, rubrum, means 'red'. The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy. Botanists have recently moved the maples into the Sapindaceae family from the older Aceraceae family.
Comparisons: This tree most easily compares with Silver Maple, A. saccharinum, which also drops its seeds in the early summer and has reddish flowers, but that tree has a more spreading crown, larger leaves that are more deeply lobed with irregular teeth and the samaras do not turn red.
Above: 1st photo - A Red Maple of about 40 years of age. 2nd photo - bark of a young tree. 3rd photo - The long scaly bark ridges of an older tree.
Below: 1st photo - Fertile female flowers developing the samaras. Drawing from Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner's Sons, New York.
Below: 1st photo - Female flower cluster before stalk development. 2nd photo - Male flowers.
Below: Detail of a cluster of female flowers with the elongation of the stalks just beginning.
Below: Samara development. 1st photo - newly formed keys (samaras) - prior to the leaves. 2nd photo - samaras developing with the leaves unfolding. 3rd photo- mature samaras.
Below - Leaves have 3 main pointed lobes with 2 smaller lobes near the base. Lobe margins are wavy with coarse teeth. The 5 main veins from the base are easily seen in the 2nd photo of the underside of a leaf. 3rd photo - fall color can be a brilliant red.
Below -Twigs are slender, hairless and reddish with small white lenticels and leaf scars in a V-shape. The buds are usually blunt varying in color from green to reddish with several scales.
Below: A leaf comparison of the common maples. Images not to scale.
Notes: Red Maple is indigenous to the Garden. Eloise Butler catalogued it on April 29, 1907. She transplanted one from Coon Lake in 1918. Former Gardener Cary George planted 30 in 1989. Curator Susan Wilkins planted 20 in 2015. It is the most widespread maple in North America being found from Ontario south to Texas and eastward to the coast except for Labrador. Michaux (Ref. #26d) generally found the species south of Latitude 48 degrees. Minnesota, on the western edge of the range has Red Maple in most counties of the NE Quadrant of the state extending down through the metro area.
Eight species of Maple are found in the wild in Minnesota: A. negundo, Box Elder; A. nigrum, Black Maple; A rubrum, Red Maple; A. saccharinum, Silver Maple; A. saccharum, Sugar Maple; A. spicatum, Mountain Maple; A. ginnala, Amur Maple and A. platanoides, Norway Maple. The latter two are not native but introductions that have naturalized.
Uses: Red Maple is used as a landscape tree and as a source of timber and pulpwood and used in furniture, veneers, cabinetry, plywood, crates, flooring, etc. Some trees produce an undulation in the grain of the wood near the circumference of the tree and when sawn this wood is called 'curly' or 'curled maple'. Another variation in the wood is when it is invaded by a fungus that leaves dark streaks in the whitish wood. This is frequently marketed as "Ambrosia Maple." The fungus enters via small holes made by a wood boring beetle. Red Maple is referred to as "soft maple" as the wood is much less hard than that of the the "hard maple" - the Sugar Maple. Red Maple rates 950 on the Janka scale vs 1450 for Sugar Maple, but being softer, works more easily with tools. Red Maple provides a sweet sugary sap for syrup but is considered inferior to the Sugar Maple, A. saccharum, and with a much smaller yield. The bark and leaves were used by Native Americans to make a decoction for use as an astringent and a tonic. (Ref. #12), however, Densmore reports no use among the Minnesota Chippewa (Ref. #5).
Botanist Francois Michaux (son of Andre) wrote in his North American Sylva of 1817-19 (Ref. #26d): "The wood ...is principally employed for the lower part of Windsor chairs. The frame, the nave, and the spokes of spinning wheels are made of it. Before Mahogany became generally fashionable in the United States, the most beautiful furniture was of Red-flowering Maple, and bedsteads are still made of it, which in richness of lustre, exceed the finest Mahogany. At Boston some cabinet-makers saw it into thin plates for inlaying Mahogany." He also stated that the wood does not burn well and was never brought into the cities for fuel.
Henry Thoreau wrote: "About the middle of May, the red maples along the edges of swamps, their fruit being nearly ripe, are among the most beautiful objects in the landscape, especially if seen in a favorable light with respect to the sun. The keys are high colored, a sort of pink scarlet commonly, dangling at the end of peduncles three inches or more in length and only a little darker shade than themselves. The lit masses of these double samara, with their peduncles gracefully arching upward and outward a little before they curve downward in order to spread the fruit and give it room, are unequally disposed along the branches, where they tremble in the wind and are often tangled by it. Like the flower of the Shadbush, this handsome fruit is seen for the most part against bare twigs, it is so much in advance of its own and of other leaves." from The Dispersion of Seeds.
Eloise Butler wrote in 1911: "The red swamp maple has glorified the lowlands with its flowers of brilliant hue, forming a pleasing contrast with the ash-gray stems. It is strange that this tree is not more often used for decorative planting, for it will adapt itself to drier sites, and would well take the place of the much admired red-bud growing farther south. The flowers of the maple are succeeded by the scarlet wings of the pendulous fruit, and, before the summer is over, the leaves will take on more gorgeous tints than the autumnal colors of other trees." From her May 7, 1911 Newspaper Article.
English poet John Clare (1793-1864) wrote this poem - "The Maple Tree"
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"