Maples group curiously well by geography. America provides big and handsome ones, given to brilliant autumn colouring. Eastern Asia contributes small and intricate ones, carefully shaped and often beautifully coloured all summer. Europe has the strong silent ones; the bull of the family, the sycamore, for instance; or the workhorse, the field maple.
Hugh Johnson, The International Book of Trees
I am often asked to name my favorite maples. Having worked with, propagated, and evaluated maples for over twenty years, this question remains almost impossible to answer.
With almost 200 species of maples in the world, many with numerous cultivars, I have limited my specialties in the nursery. I have also concentrated my study and propagation efforts on the Japanese maples (Acer palmatum) and the other maples of Japan, such as A. capillipes and a few other outstanding and interesting species. The term Japanese maple in commercial horticulture embraces A. palmatum and a few related species, plus their cultivars.
Many decades ago the term Japanese maple usually meant, to the average gardener of the day, the red laceleaf, small weeping tree Acer palmatum ‘Dissectum Atropurpureum’. Some were aware of a laceleaf maple with green leaves. Some nurseries and a few well informed gardeners also knew, and planted, the upright forms of Japanese maples. These red or green-leaved trees grow to fifteen or twenty-five feet and usually have wonderfully bright fall colors. Some of the best of them were selected for outstanding characteristics of form or leaf shape or color. The Japanese had been doing this for over 200 years, but their selections were slow in reaching us in the West.
In the last ten or fifteen years interest in this group of plants has increased enormously. Many articles, and at least one book on the subject, have made the public aware of the tremendous variety existing today. In my work with Japanese maples I have grown and propagated over 250 cultivars and collected for study more than seventy-five others. In the process, many of the trees have reached maturity, and I have had the opportunity to observe their best features as well as their limitations. Gradually, of course, some kinds begin to impress me for their beauty, distinctiveness, and dependability in cultivation. Admitting, then, to a preference for some over others, I will list those that have left an indelible impression after many years of close observation.
Among trees of Acer palmatum with upright (as distinct from weeping) habit, the cultivar ‘Sango Kaku’ has small green leaves that blend into the summer landscape. But in fall it can be relied upon to produce magnificent yellow and orange coloration, and in winter it is famous for its brilliant coral bark. The larger dark green leaves of ‘Osakazuki’ turn vivid crimson in fall, the most brilliant of its kind. When available from nurseries, green-leaved seedlings of A. palmatum var. heptalobum can be used in mass plantings that produce exceptionally bright red and orange colors in fall. This is a valuable economy for those needing many trees in large landscapes.
Upright maples with red or purplish leaves all year are many. The old standard ‘Bloodgood’ is surely dependable. Dick Wolff of Media, Pennsylvania, registered the cultivar ‘Moonfire’, which holds its red color unusually well throughout the seasons. I must also mention ‘Nuresagi’, which I feel is an outstanding red cultivar, not as well known as it should be. The leaves are black-red, and they hold their color well throughout late summer and into fall.
My favorite red-leaved tree among the ‘Dissectum’ group is ‘Tamukeyama’. It has a rich maroon color that does not fade or bronze out in late summer heat. Its fall color is excellent, and I find it holds it better than most well known cultivars. A good choice among the green-leaved kinds is ‘Waterfall’, a dependable cultivar from the famous plantsman Henry Hohman. ‘Sekimori’, too, is a fine plant, with attractively striped bark on young branches and deep green leaves that turn bright yellow in fall. The lovely ‘Filigree’ is described as variegated, but the golden flecks in the green spring foliage are subtle. Laceleafs generally form low, broadly mounded plants, but there is one notable exception named ‘Seiryu’ that makes an upright small tree of medium size. The characteristic laceleaf foliage on an upright tree gives an effect like no other.
Upright cultivars of Acer palmatum var. matsumurae have deeply divided leaves with long serrated lobes. One of these, a striking tree with green leaves, is ‘Omurayama’, which develops a slightly drooping form as it matures. In fall the leaves take on hues of pumpkin and flame. The vigorous upright ‘Matsu kaze’ starts the year with bright reddish leaves that turn green in summer and carmine and red again in fall. An especially fine round-topped maple with purple-red leaves is ‘Suminagashi’. This lovely tree has beautiful red seeds that hang in clusters in fall.
Acer palmatum ‘Linearilobum’ adds a distinctive texture to gardens quite unlike that of other Japanese maples. The long, narrow leaf lobes are less delicate than those of the laceleafs, but nonetheless elegant. The cultivar ‘Scolopendrifolium’, green-leaved and vigorous, is the most readily available. A red-leaved tree of this kind, ‘Red Pygmy’, grows to medium height and yields a lovely plant.
Outstanding among dwarf plants of Acer palmatum is ‘Coonara Pygmy’, selected and named by Arnold Teese of Australia. It makes a dome-shaped plant with tiny green leaves that turn a magnificent orange-red in fall. Entirely different from this green dwarf is ‘Mikawa Yatsubusa’, a dense and compact plant with stubby growth thickly covered with dark green leaves. The best red-leaved dwarf in our landscape is ‘Aratama’. The foliage is bright purple-red until the heat of midsummer, when, like most red maples, it takes on a bronzy hue. This is a compact plant excellent for accent planting. ‘Garyu’ is a rock garden dwarf with unmaple-like green leaves. The thin shoots appear delicate, but it is a tough little plant.
Visitors to my maple collection either shudder at trees with variegated leaves or are greatly taken with them. The prominent ‘Ukigumo’ has green leaves heavily mottled with cream and pink. For a variegated maple it does well in the sun. ‘Shigitatsu sawa’ has a more organized pattern of pale yellow-green leaves with veins outlined in brighter green. It makes a strong tree in the landscape. And, of course, one must not overlook the remarkably popular ‘Butterfly’ with its tiny green and cream, irregularly shaped leaves on twiggy growth.
Some maples make my list because of some unusual feature that sets them apart. The flaming red leaves of ‘Shindeshojo’ in early spring welcome the season of maple foliage. The unusual narrow, upright growth of ‘Okushimo’, with small, pointed, intensely lemon-yellow leaves that curl at the edges, is a distinctive feature in any garden. The dependable ‘Shishigashira’ is neatly upright with crinkled leaves tightly packed along sturdy stems. Dwarfer is ‘O-jishi’, which fits nicely into smaller plantings. And ‘Kamagata’ attracts attention wherever it is planted. A delightful choice, it makes a small to large bush and is especially noted for its delicate appearance with tiny leaves, compact, twiggy growth, and fire-red fall color.
The Japanese maples are easily grown small trees. They should not be planted deeply — the roots remain quite shallow. They should have well drained soil and not be kept too wet; overwatering causes more problems than anything else. The tops will stand below-zero temperatures, but roots must have winter protection if grown where soil freezes deeply. Mulching prevents damage in severe winters. Fertilize sparingly if at all; otherwise lank growth may occur. Japanese maples are excellent companions for rhododendrons, azaleas, dwarf conifers, and many other shrubs.
There are exceptional plants also among maples closely related to Acer palmatum. The superb A. japonicum ‘Aconitifolium’ is a medium-sized tree with fern-like foliage. The fall blaze of intense red it produces is worth waiting for. Similar in leaf, but with weeping growth and mounding habit, is ‘Green Cascade’. The contrast of soft green young foliage and intense fall color is dramatic. For sheer brilliance in fall, the upright A. japonicum ‘Oguryama’ has few equals.
While thinking of fall color, I must mention two mid-sized trees of exceptional merit. Siebold’s maple, Acer sieboldianum, colors intensely even in irrigated landscapes where vine maple (A. circinatum) fails to make a fall show. A second excellent tree with the clumsy name of A. shirasawanum ‘Palmatifolium’ can be found in some nurseries and is worth the search when a strong-growing green-leaved tree with striking fall color is wanted. The golden full moon maple, A. shirasawanum ‘Aureum’ (similar to A. japonicum ‘Aureum’), is increasingly available in nurseries. It is a lovely round-topped tree from Japan with yellow-green spring foliage and good fall color.
For the landscape that will accept larger trees, there are some choice plants. The well known paperbark maple, Acer griseum, with peeling, tissue-paper bark exposing smooth bronze layers beneath, has deep green leaves that turn scarlet in fall. There are also two striped bark maples on my list: A. rufinerve, with leaves of unusual texture, green-striped bark, and orange-red fall color; and A. pensylvanicum ‘Erythrocladum’, a cultivar of our eastern native, with coral bark that stands out in the winter garden. Two trees with unmaple-like leaves are A. pentaphyllum, with long, five-lobed leaves (there is a good specimen in San Francisco’s Strybing Arboretum), and the hornbeam maple, A. carpinifolium. Although larger, and not as well known as most Japanese maples, these trees are distinctive and bring variety and interest to larger gardens where the genus is featured.
This is a rather long list of favorites, but even so I fear that some worthy trees have been omitted. No group of trees offers such elegance and color for our gardens as maples do. I must admit I like them all.