by Randy Davis 

This is the second part of this article on maples. The first part appeared in the May 2008 issue - ED

The Species

buergeranum (Trident maple) – The trident maple is one of the stalwart maples in bonsai.  It has been used for many years and conforms to all of the needed requirements to make an outstanding specimen or group bonsai.  It is easily found at bonsai shows and becoming more available in the commercial nursery trade. When trees grown are from seed, they will usually conform to one of two types. Type I is a tree with smaller leaves and very good inter-node length and is the preferred form for the smaller bonsai under 12 inches.  Type II is a tree with somewhat larger leaves and longer inter-nodes with a flaking bark that forms on younger trees.   The buds form on the branches in an alternating pattern with one set of buds in the horizontal position on the branch and the next pair of buds in the vertical position. You can use this to your advantage when you are pruning for shape.  There are a number of cultivars, including a variegated leaf form.

campestre (English Hedge Maple) – Not often found in the American bonsai community, but is used extensively in Europe.  This is an excellent bonsai subject with very deeply lobed leaves, apple green in color.  Hedge maple has the habit of longer internodes than one would like, but with diligent pinching it can be kept under control. It is a fast growing tree and will form a very nice crinkled bark rather quickly on a tree at 5 years or so.  If you enjoy working with maples, this would be a fine addition to your collection.  Acer campestre is somewhat difficult to find but well worth looking for at bonsai shows.

carpinifolium (Hornbeam Maple) – This species is not often found in bonsai outside of its native Japan but will make a wonderful larger size bonsai.  The leaves are oval in shape and have deep veins, making it very reminiscent of Hornbeam (Carpinus).  The inter-nodes are large and the wood is very straight grained, which is the reason it will not perform well for bonsai under 18 inches or so.  The leaves are vivid green during the growing season without any significant coloration in the fall other than the typical yellow and brown.

circinatum (Vine Maple) – The vine maple is used for bonsai far more on the West coast of the United States and, in particular, in the Northwest, where it is native to the woodlands of Oregon and Washington state.  To the untrained eye, it is often mistaken for Acer japonicum because of the similar leaf structure.  It is differentiated from japonicum by its very long internodes which are very long, with branches often weeping to the ground (from which its common name is derived). Leaf reduction is moderate, but because of its long internodes, it is better suited to the larger size of bonsai.  The leaves are apple green in color during the summer months, becoming a lovely butter yellow in the fall. 

cissifolium - One of the only trifoliate maples that will work well for bonsai due to good leaf reduction characteristics not found in our American native Acer negundo.  Native to the mountain forests from southern Hokkaido to central Kyushu in Japan.  The internodes are moderate and can be controlled well with adequate pinching.  The leaves will maintain a very small size in bonsai culture for a trifoliate maple. The emerging leaves are pinkish red in color in the early spring, and the bark is a light cinnamon color, making for a lovely display.  Rather difficult to find, but if, you’ve ever been enticed to try a trifoliate maple, this is the one to use. No fall coloration.

davidii (David's Maple) – David’s maple is a native of  central and Western China.  The leaves are generally oval (lanceolate) in shape 5-6 inches in length, and leaves reduce moderately.  The leaves are a rich dark green with the leaf petiole and leaf veins red in coloration, making for a very nice contrast.  Being a small multi-trunked tree by nature makes it a natural for the double trunk design type of bonsai.  The most interesting part of this tree is the striped bark.  Even from a young age, the bark is a dark green with pinkish striping, and when mature is a dark green with white stripes.  This is one of those trees that would make a wonderful winter-viewing bonsai because of the unique bark. This is one of those trees that you should start out as a young tree for development and avoid trunk chopping.

ginnala (Amur Maple) –  This is one of the more commonly used maples for bonsai.  It has excellent leaf reduction and internode characteristics.  The leaves are 3-5 inches with 3 lobes and serrated leaf edges. Leaves are a nice rich green and are often spotted with small pink spots in early spring.  The bark of older established trees is a wonderful bright grey coloration.  They can be field grown, trunk chopped and then grown out to large caliper trunks in 5-7 years.  They are impervious to root pruning. Amur Maples are very cold-tolerant, making them excellent candidates for the northern climates with little or no winter protection needed.

japonicum (Full Moon Maple) – I only include this tree in the list because it is one of the favorite trees of people who collect maples.  The leaves are round, 5-7 inches in diameter, with 7-9 lobes of an apple green color.  There are upwards of 75 cultivars known, of which only a handful are available through the specialist nurseries.  The internodes are rather large as well as the dormant buds of this tree.  While I have seen some small examples (under 12 inches) as a bonsai, they are often without much visual interest.  This is one of those trees that would be far better suited to bonsai in the 18 inch and larger format. Cultivars are often grafted, so care should be taken in selecting a tree for bonsai that has a low cleft graft so it is not quite so noticeable.

monspessulanum (Montpellier Maple) – A small shrub type maple native to southern Europe. Not often seen in the United States, other than in horticultural collections of universitys or enthusiasts.  This tree has a small 3-5 inch leaf that is 3 lobed with a smooth edge.  It leaf reduces quite nicely. Internodes are moderate in length, but the branches seem to be quite stiff and straight, so frequent pinching is required to make them into nice bonsai.  The bark of the tree is nicely furrowed, with age adding to its visual interest as a single tree specimen. The tree is fairly difficult to find but worth it as a welcome addition to your broadleaf tree collection.  Propagated exclusively by seed, of which only 10 percent are viable.

palmatum (Japanese Maple) - The Japanese maple has been in formal cultivation in Japan since the 17th and 18th centuries. For bonsai, it makes sense that its use has also been long and fruitful.  Over the years, there have been many hundreds of cultivars developed, many still in cultivation, and many that have probably been lost.  From a care perspective, treatment of the cultivars is the same as the species with the exception of pruning.  The dwarf forms requiring little to no pruning (other than design considerations) at all because of their short internodes. The bark of the species when young is bright green and turns to a beautiful grey with age. The cultivars may vary from the normal green bark when young to brilliant red, as is the case with Sango Kaku, or dark purple with those in the Blood Good (ssp: amoenum) group which will all turn the typical grey with age.  Leaf size will also differ between the sub-species: a smaller leaf for the palmatum group (ssp: palmatum) and the Blood Good group which usually larger by half. These leaf sizes will have an impact on the size of the bonsai to keep it in perspective.  Because of the number of variables in this species, it is an excellent choice for bonsai and will provide the enthusiast much to consider in selection and use. Of particular interest is the cultivar “arakawa” which has a wonderful cork bark that is so unusual in the Maple family.

pensylvanicum (Striped Maple) - An American tree native to the east cost from the North facing slopes of the Appalachians, north to Nova Scotia and west to Minnesota.  Pensylvanicum is a tree with good potential as a larger bonsai specimen at 24 inches, and larger.  Leaves are 3 lobed and rather large at 6-8 inches, but can be reduced by half with good growing and pinching techniques.  The tree is one of the few “snake-bark” forms, with conspicuously striped branches and trunks with wide white stripes.  This tree should be used as a winter-interest tree, as the bark will turn reddish with wide, distinctive white stripes.  Again, as with the other trees used for this purpose, trunk chopping should be avoided.  For those interested in collected trees, it is usually found as an under-story tree and frequently found with A. saccharum and A. rubrum in their native habitats.

pseudoplatanus (Sycamore Maple) - This tree is used far more in Europe for bonsai since that is native to that part of the world.  The leaves are medium in size 5-7 inches with 3 to 5 lobes, with sharp points at the leaf lobes, making them reminiscent of our native American Sycamore.  I have seen some smaller examples of the tree in bonsai, but in my opinion would be much better suited to the larger size of bonsai not less than 24 inches.  Bark will peel in small scales with fissuring in large vertical strips on the trunk.

rubrum (Red Maple) – This is the predominant tree here in the Midwestern United States and not used for bonsai nearly enough.  Leaves are 3-5 lobed and 4-6 inches on a mature tree but are very good at reducing in size to 3-4 inches or smaller under bonsai cultivation.  Internodes will vary from large on a vigorous new shoot to very small on a tightly ramified branch.  Vigorous pinching is required to maintain good branch structure on a smaller tree.  I think that a tree in the 24-36 inch range is optimum for this species.  This tree is dioecious, meaning that there are male and female trees of which the male trees are better for use as bonsai.  The male trees are vigorous growers, where as the female trees are rather spindly and weak.  Red Maple will not only make a wonderful tree during the summer months, with bright green leaves, but will also put on a lovely display of fall coloration in the yellow to red ranges. From my perspective, the best time for this tree is in the early spring when it puts on a wonderful flower display of bright red flower bundles before the leaves emerge.

Saccharum (Sugar Maple) – This is another American native tree that is little used for bonsai like the Red Maple and should be used far more than it is.  It is best suited as a medium to large bonsai and will reward its owner with that lovely fall coloration for which it is so well known.  The leaves are 3-5 lobed and 4-6 inches and will reduce moderately.  Inter-nodes are rather straight and should be pinched often to give the tree a more interesting looking format.  The wood is also very tight grained and hard which requires mid-fall wiring, otherwise they are known to break readily.

truncatum (Shantung Maple) – This tree is a native of China and fairly difficult to find, but well worth the effort.  While the leaves are rather large on this tree, with some pruning, they can be reduced to an acceptable level.  The leaves are 5 lobed and 4-6 inches across, and can be reduced to half their normal size.  In the early spring, the leaves emerge a bright apple green with a purple cast over the leaf edges and leaf veins, making for a lovely sight.  The largest problem with this tree is the inter-node length, so pinching on a regular basis is required.  As a medium size bonsai in the 16-24 inch size it will make a wonderful tree.  The bark of this tree is its best asset and will give you many wonderful hours of winter enjoyment.  The bark is very rough and fissured, more so than any of the other Maple species and has a lovely white-cinnamon coloration.  With the bark coloration and fissuring, from a distance it looks as though it is white with black stripes and really catches your eye.  Well worth the effort if you can find it.