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The Monday Garden
Shades of Maple: Tree Identification Guide
Issue No. 0134 - October 16, 2004
by Sue Sweeney
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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). |
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picture: sugar maple Hillandale Ave, Stamford CT October
2004 |
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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. |
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pictures: sugar maple leaves
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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. |
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pictures: red maple leaves
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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. |
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pictures: silver maple leaves |
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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. |
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picture: Norway leaves |
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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. |
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picture: sycamore maples leaves |
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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. |
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pictures: buds of sugar, red and Norway
maples |
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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. |
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picture: flowers of sugar, silver
and Norway maples. |
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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. |
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pictures: red maple bud, flower and
beginning seeds |
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THE SEEDS (“SAMARAS”): The maples seeds are another
major ID point. The seeds come in winged pairs call
“samaras”. |
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pictures: seeds (samaras) of sugar, red
and Norway maples |
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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 (¾”),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. |
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picture: seeds of silver and
sycamore maple
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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. |
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pictures: bark of sugar, red and
Norway maples
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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. |
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picture: Sugar maple with multiple
crotch branches and a silver maple with multiple trunks; both from
Scalzi Park Stamford CT 2003 |
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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. |
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