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The Monday Garden
Shades of Maple: Tree Identification Guide

Issue No. 134 - October 16, 2004
by Sue Sweeney

  
Admit it, maple trees are interesting. There’s the family drama of the reds and the silvers who do so much for our wildlife; and the sugars who provide a valuable food as well as breath-taking beauty. Then there are the Norways and other foreign maples that that threaten our native plants (and your lawn).
 
picture: sugar maple Hillandale Ave, Stamford CT October 2004
 
There are about 14 North American native maples-- few enough to know them all personally. The major ones in the Northeast are the sugars (Acer saccharum), reds (Acer rubrum) (also called “swamp maple”), and slivers (Acer saccharinum). In addition to the Norways (Acer platanoides), the common imported maples include the Japanese (Acer palmatum, Acer japonicum, etc.), sycamore (Acer pseudoplatanus) (not the native tree know as “sycamore” – but a type of maple), and amur (Acer ginnala). Maples are prolific and cross-breed so there is always a bit of individual variation between trees, making the identification an interesting challenge but not so hard that it has to be left to experts.

Because the maples have cross-over characteristics, it’s always best to use at least two features to confirm identification. Each maple had at least one characteristic that’s unique to it.

Distinguishing maples from other trees – opposite leaves and branches: All maple leaves and twigs come in pairs that are opposite each other on the branch. This is uncommon among native trees in the Northeast, where most trees have alternating leaves and twigs. The only other major family of native Northeast trees with opposite leaves and branches are the ashes.

 

THE LEAVES: All local maples have simple leaves (i.e. not divided into leaflets) with veins radiate from a single point at the leaf base (palmate veins) and long stems (petioles). The box elder (Acer negundo) (which will be the subject of a future article), is the one native maple that breaks this rule; it has compound leaves (leaf made up of several leaflets).

The leaves of Norways, reds, and sugars often look much alike. Of these three, only the reds have V-notched sinuses (the depressions between the leaf points) and a toothed leaf margin. The sugars often have wavy, smooth margins, and the Norways have smooth margins and milky petiole (stem) sap.

The red maple is NOT red-leafed. The red maple has reddish buds and flowers, and may have red leaf stems and red fall color but the summer leaf is green. The maples with mature red leaves are aliens including the Norway variety known as “Crimson King” (leaves may look burgundy or almost black) and some of the Japanese maples. Many maple saplings, regardless of variety, have red or bronze new leaves.

 
pictures: sugar maple leaves
 
Sugar: The sugars have medium size leaves (3-6”) that are medium to dark green on top, and lighter underneath. They almost always have 5 pointed lobes, curving sinuses (indentations), and wavy but smooth (not toothed) leaf edges (margins). The bottom 2 lobes are smallest. Fall: yellow, orange or red; can have any or all colors; colors can mixed with green, colors can be sequential.
 
pictures: red maple leaves
 
Red: The reds have a smaller leaf (2” - 4”). The leaves are medium green to gray-green, with noticeably white undersides. The reds sometimes have red leaf stems (but so can other maples). The reds’ leaf sinuses (indentations between leaf points) are always v-notched—not curved, and the leaf margins are always toothed – not smooth. The three major leaf lobes will usually point forward. The reds may also have 2 small bottom lobes. Fall: red, burgundy, yellow or calico.
 

pictures: silver maple leaves

 
Silver: The silvers have medium to large leaves (3”- 5”) which are pale to bright green and silver underneath. The silvers are the only ones with deeply cut U-bottomed sinuses that make the leaves look lacy. Like their cousins, the reds, the silvers have toothed leaf margins (edges). Fall: green, yellowish green, yellow, occasional red.
 

picture: Norway leaves

 
Norway: The Norways have large, broad leaves (4”- 7”)with dark green tops and lighter undersides. The sinuses (indentations) can look like webbing of a duck’s foot. If you break off a leaf, you’ll see a milky white sap at the base of the stem; none of the native maples have white sap. The Norways leaves can have 5 or more pointed lobes– I’ve counted 11. The bottom 2 lobes are smallest. Fall: usually butter yellow but can be orange to red; some early turning Norways turn burgundy.

Japanese: The Japanese maples vary according to cultivar but usually have small to medium leaves (2” -5”) with lance-shaped lobes, sharply pointed at the tips, v-notched sinuses, doubly serrated (toothed) margins; and an odd number of points. Fall: color depend on variety.

 

picture: sycamore maples leaves

 
Sycamore: The alien sycamore maple has medium to large, broad leaves (3”- 6”), with a dark green, heart-shaped base, v-notched sinuses, 5 to 11 rounded or oval lobes, and a coarsely toothed leaf edge. Fall: yellowish, considered non-showy.

 

BUDS AND TWIGS: Almost all maple tree buds start out as tiny triangles peeking out of the leaf axils and at the twigs’ terminal ends. By early fall, most buds are developed enough to use for identification.

 

pictures: buds of sugar, red and Norway maples

 
Sugar: The sugars have small, hard, dark buds covered with tight, rounded scales. One at the branch terminal and one in each leaf axil. To me, the buds resemble the spire of an art deoc building.

Red: The reds’ buds are tiny round reddish balls. There will be three buds in each leaf axil and a cluster at the branch terminal (usually 9 – three for each side axil and three for the terminal bud).

Silver: the silvers also have clusters of red buds but they are somewhat irregular in shape and larger than reds. They also develop later in the fall. The twigs of the red and the silver are said to produce a bad odor when broken.

Norway: The Norways have stout, smooth twigs; the buds are also fat. The buds are maroon or lime green or both colors. In the fall, the buds look to me like baby turtles’ heads emerging from the shells. The buds swell very large in Spring --like boxing gloves or turbans on a stick.

Japanese: The Japanese have very slender twigs; the buds are often tiny, red, and shiny. The terminal bud is missing.

 

THE FLOWERS: Yes, trees flower and the maples have beautiful ones. The spring bloom order is silver, red, Norway, sugar.

 

picture: flowers of sugar, silver and Norway maples.
 
Sugar: The sugars have tiny, olive green flowers on long (1-3”) tassels, almost like the oaks.

Red: The reds’ flower clusters, from a distance, look like fuzzy red balls or pom-poms; female flowers are showier with redder color.

Silver: The silvers’ flower clusters are flowers similar to reds but more red-orange and not as showy.

Norway: The Norways have fist-size, showy “bouquets” of small lime green flowers; some cultivars can have red or maroon sepals around the flowers. (I hate to admit it but the Norways flower are one of my favorite spring sights).

Japanese: The Japanese maples’ flower color and season vary by cultivar.

 

pictures: red maple bud, flower and beginning seeds
 
THE SEEDS (“SAMARAS”): The maples seeds are another major ID point. The seeds come in winged pairs call “samaras”.
 

pictures: seeds (samaras) of sugar, red and Norway maples

 
Sugar: The sugars’ samaras appear later than those of the other local maples and can look reddish over summer. They don’t mature until fall. Sugar samaras have more downward curve (horseshoe-shaped) and rounder, plumper seed cavities.

Red: The reds’ samaras are small (”),and reddish or rusty-tan in color with a medium angle. They drop off as soon as they ripen (May- June) and the wings often break apart quickly.

Silver: The silvers have very large (1”- 2.5”) golden tan samaras with a medium angle. They also drop off as soon as they are ripe (May- June) and the wings usually break apart quickly.

Norway: The Norways have large (1-2”), green samaras, maturing to tan. The winged pairs are relatively flat, and are set at wide angle, curving up at end. The pairs usually hold together. The much-too-prolific Norways sheds seeds from mid-spring through late fall or winter.

Japanese: The Japanese have medium to small samaras, often reddish; with wings at 60-90 degree angle.

Sycamore: The sycamores have medium large samaras (1.5”-2”), at 60-90 degree angle. The seeds mature to tan late summer and hang in clusters.

 
picture: seeds of silver and sycamore maple
 
BARK: Almost all young maples have smooth barks, often gray or gray-brown. As the trees mature, the reds, silvers and sugars become rough and shaggy; the Norway’s stay smooth but become craggy. It can be impossible to tell the sugars, reds, and silvers apart by the bark alone, as they can all be about the same degree of shaggy at certain stages in their development. However, if the bark furrows are so beautiful that they take your breathe away; you’re looking at a sugar. If the barks furrowed or shaggy, you know it’s not a Norway.
 

pictures: bark of sugar, red and Norway maples
 
Sugar: Mature sugars have beautiful, gracefully curving, irregular, silvery gray furrows.

Red: Mature reds have deep, irregular vertical gray furrows.

Silver: Mature silvers have very shaggy, gray or silver furrows; look for showy orange under-wood.

Norway: Mature Norways have gray or gray-brown, smooth-ish bark with shallow, long, narrow, somewhat interlacing ridges; looks to me like the hide of an ancient, hairless animal.

Japanese: Mature Japanese maples can have gray, smooth bark with light vertical stripping; some varieties have decorative bark – even tricolor and curling.

 

picture: Sugar maple with multiple crotch branches and a silver maple with multiple trunks; both from Scalzi Park Stamford CT 2003

 
SHAPE (HABIT AND FORM):
It can be hard to tell maples apart by their shape since so many of the trees have had their shapes altered by pruning, crowding, or other cause. Some times though, shape, can help.

Sugar: The sugars are prone to several major low-growing, spreading crotch branches, the mature trees can be shaped like up-side down heart.

Red: The reds often grow in clumps from a stump; in the forest, they often have high bottom branches.

Silver: The silvers are often multi-trunk with spreading branches, sometimes vase-shaped, with “droop and swoop” branches.

Norway: The Norways usually have two or three major branches sloping upward and dense rounded crown, can be wider than tall.

Japanese: small tree, graceful multiple trunks, horizontal layers; bottom braches low.

Sycamore: upright, wide-spreading crown, short trunk.

  
From The Monday Garden. Copyright © by Sue Sweeney. Reproduced with permission. 

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