Maples for Autumn Color
By Geoff Bryant
As the weather cools in late summer and the days shorten noticeably so
the deciduous trees and shrubs begin to withdraw chlorophyll from
their leaves in preparation for the winter shutdown. With less of that
vital green pigment to mask them, the other colors within the leaves
begin to show through.
While the best of the autumn color may be over
for this year, the coming winter months are the time to consider how
best to prepare for next years autumn glory.
When it comes to the most vibrant tones, the genus Acer, the maples,
includes many sterling contributors. Most of the 150-odd species of
maples are deciduous trees, though some are shrubby and a few are
evergreen.
Acer is primarily a temperate northern hemisphere genus,
ranging from around 59°N southwards to the mountains of the
subtropics. With the exception of a few Eurasian species, principally
the Norway Maple (Acer platanoides) and the Sycamore Maple (Acer
pseudoplatanus), most of our garden maples are derived from Asian and
North American species.
Maples do flower, but apart from a few with showy tassel-like blooms,
most are grown solely as foliage plants, And while the thrust of this
article is about autumn color, many of the best autumn maples are also
excellent spring and summer foliage plants.
Of course, getting good autumn colors depends greatly on the climate
and the shades vary from year to year even in districts known for
their autumn foliage. Generally the best colors develop during a
prolonged autumn with warm, still days and cool but not freezing
nights. Soon after the first frosts strike the last leaves fall.
Although most maples color to some extent in autumn, the following
species and their cultivars are readily available and among the
brightest and most reliable.
Acer buergerianum -
Trident Maple
This 10-12 m tall, round-headed tree eastern China and Japan gets its
common name from the leaves, which usually have three lobes. The
leaves are small and primarily red in autumn, with tints of orange and
yellow.
Acer cappadocicum -
Caucasian Maple
Found from the Caucasus to northern India, broad-crowned, 15-20m tall
tree is best known for its bright golden yellow autumn foliage.
Cultivars include 'Aureum', with yellow foliage in spring and autumn,
and 'Rubrum', which has bright red young stems and spring leaves.
Acer davidii -
Snakebark Maple
Best known for its white-striped and flecked green to purple bark,
this 15 m tall Chinese species has 3-lobed or unlobed leaves that
often color brilliantly in red, gold and orange tones before falling.
'George Forrest' is a large-leaved cultivar.
Acer griseum -
Paperbark Maple
Again, best known for its bark, which is warm brown and peeling, the
foliage of this 5-10 m tall Chinese tree turns bright red in autumn.
Because of the red-brown bark, the foliage color can seem muted and is
perhaps best seen at a distance where the color of the whole tree can
be appreciated.
Acer japonicum -
Full-moon Maple
This slow-growing Japanese native is a small tree with tiered branches
and 7-11-lobed leaves that can be almost round in some forms. The
autumn colour is a combination of bright red and yellow on a green
background. The Fernleaf Full-moon Maple, 'Aconitifolium', has very
finely divided foliage reminiscent of aconite leaves.
The Golden Full-moon Maple (Acer japonicum var. aureum) has rounded
lime green spring leaves that become yellow as they mature then turn
golden and red in autumn. It is now more properly known as Acer
shirasawanum 'Aureum'.
Acer palmatum -
Japanese Maple
Everyone knows the beautiful Japanese maple with its seemingly endless
range of cultivars in every imaginable leaf shape and colour.
Originally found in Japan and Korea, it has been highly refined and
developed by both Japanese and Western gardeners.
Regardless of its preference for cool, humid conditions and a tendency
to develop die-back, the Japanese maple is nearly everyone's favourite
small tree. The autumn foliage color of the purple- or red-leaved
forms is usually just a more intense shade of the summer color, while
those with green to pale gold leaves develop shades of red, orange,
gold and yellow.
For autumn color consider: 'Bloodgood', deep red; 'Aureum', deep gold;
'Beni Kagami', bright red; 'Hessei', red; 'Dissectum', bright orange;
'Dissectum Atropurpureum', red; 'Linearilobum Atropurpureum', bronze;
and 'Linearilobum Rubrum' bright red.
Acer platanoides -
Norway Maple
Found from northern Europe to the Caucasus, the Norway maple is a
strong-trunked, round-headed tree to 30 m tall, with 5-lobed leaves up
to 18 cm wide. While the species has deep green leaves that rarely
develop much color before turning brown and falling, some of the
cultivars offer brighter hues. 'Schwedleri', in particular, is a
purple-green form that often reddens intensely in autumn. 'Goldsworth
Purple' can develop similar tones.
Acer rubrum -
Red, Scarlet or Swamp Maple
Native to the eastern United States, this fast-growing 20 m tall tree
has 3-5-lobed leaves up to 10 cm wide that color well in the autumn,
developing intense red and gold tones. This species is occasionally
tapped for its syrup. 'Columnare' is a broadly columnar cultivar, not
to be confused with A. platanoides 'Columnare'. 'Red Sunset' has
particularly good autumn foliage.
Acer saccharinum -
Silver Maple
Often confused with the sugar maple because of their similar botanical
names, the Silver Maple is found over much of eastern North America,
grows quickly to around 40m tall and has an open crown. Its large
leaves have silvery undersides and are red, orange or gold in autumn.
Acer saccharum -
Sugar Maple
This species, widespread in North America, is both a timber tree and
the source of maple syrup, which makes it the most commercially
important maple. As it was the pattern for the maple leaf on the
Canadian flag you might think it would have red autumn leaves. Well,
sometimes it does, but it is very variable; sometimes red, other years
orange, gold or combinations of colors.
Acer tataricum -
Tatarian Maple
Found over much of the temperate northern hemisphere outside Europe,
this 10m tall tree has rounded, toothed leaves that turn vivid shades
of yellow, orange and red in autumn. The Amur Maple (Acer tataricum
ssp. ginnala), from Siberia, northern China and northern Japan, is
shrubby, extremely tolerant of wind and cold and has red autumn
foliage. It used to be classified as Acer ginnala, and is often still
sold under that name.
Cultivation tips
Except for a few species, maples are generally very hardy. They prefer
a deep, well-drained, fertile soil with plenty of humus. For the best
autumn tones plant in a sunny position but try to provide good wind
protection, at least for young plants and Japanese maples, or the
foliage may burn or fall before it has a chance to colour well.
Maples respond well to light winter pruning when young and are best
shaped to a fairly round crown on a sturdy trunk. Some, such as Acer
palmatum, tend to be fairly shrubby with low forking and these are
best left to develop naturally.
Even though the exact autumn shades are difficult to predict and will
vary from year to year, you won't go far wrong with maples. They're
beautiful enough in any season to forgive them their vagaries.
Did you know?
It takes around 43 liters of Acer saccharum sap to produce 1 liter of
maple syrup. A good sized sugar maple yields around 50 liters of sap
and during the processing into syrup the sugar concentration rises
from 2% to 66%. No wonder it's so sweet, but what a flavor!
I am a garden book author and horticultural photographer based in
Christchurch, New Zealand. I run a stock photo library called Country,
Farm and Garden (http://www.cfgphoto.com). This article may be
re-published provided this information is published with it and is
clearly visible.
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