‘Tsuma gaki’ Japanese Maple Has Glowing Spring Color
By Corinne Kennedy
The spring foliage of Acer palmatum ‘Tsuma gaki’ is bright yellow-green, tipped in red—and beautifully echoed by the tree’s dainty red flowers. (photo: Aleks Monk)
The Seattle Japanese Garden is deservedly popular in autumn, when thousands of visitors view the brilliant fall colors of its Japanese maples. It saddens me, though, that the beauty of their spring foliage is less often appreciated. One of our Garden’s Japanese maples with gorgeous spring foliage—and one my favorite trees—is Acer palmatum ‘Tsuma gaki,’ with bright yellow-green leaves tipped in brilliant red. In fact, the Garden has two trees, planted in 2010 and 2011. One is located in Area B, just past the entry gate, in the small courtyard west of the main path. The other is in Area D, further along the east side path, midway between the path and the fence.
Japanese maples and their cultivated varieties (cultivars) are iconic elements of Japanese Gardens, including our own. Many maple species are native to Japan, revered there since the 7th century, and represented in its literature, painting and other arts. During the Edo period (1603-1867), horticulture flourished, and more than 200 maple cultivars of unique beauty, color and form were created. They were derived from the two species commonly known as “Japanese maple” (Acer palmatum and Acer japonicum). More recently, many hundreds more have been developed, not only in Japan but throughout the temperate world. To characterize them more easily, they’ve been organized into groups—including Amoenum, Palmatum, Matsumurae, Linearilobum, Dissectum, and Dwarf.
‘Tsuma gaki’ belongs to the Amoenum Group, one of several that are based on how the leaf lobes are divided. Trees in this group have leaves with 7-9 broad, finely toothed lobes that are shallowly to moderately divided—up to two thirds of the way to the leaf base. A good example is Acer palmatum ‘Osakazuki,’ renowned for its vivid crimson fall color.
Botanically, all maples are classified in the genus Acer, a name derived from the Latin word for “sharp—and a reference to the pointed leaf tips of many maple species. Our Garden’s showy cultivar, ‘Tsuma gaki,’ was bred from the species Acer palmatum, which has given rise to many more cultivars than any other maple. Its specific epithet is a reference to the palmate (palm-like) shape of its leaves. Typically consisting of 5-7 lobes, they resemble a hand with outstretched fingers. The cultivar name ‘Tsuma gaki,’ which means “red nail,” is a fitting acknowledgement of its lovely scarlet-tipped spring foliage.
The ‘Tsuma gaki’ Japanese maple planted in Area D, its brightly colored spring foliage on display. (photo: Aleks Monk)
Acer palmatum ‘Tsuma gaki’ is a rather slow-growing Japanese maple—at ten years about 6-8 feet tall and 4-6 feet wide. At maturity (20-25 years), it will be about 12 feet tall, with a dense, layered, and rounded habit, wider than tall. Young trees often benefit from staking to support the weight of leaves on the young branches. This will prevent them from developing into mature trees with unattractive proportions—quite short but very wide-spreading.
Leaves are medium-sized, lightly toothed, and divided into five (sometimes seven) lobes, separated about ½ way to their base and tapering to slender tips. They open rather slowly, with a pendant, cupped appearance that has been described as looking like soft flowers unfolding. Other observers liken them to a flock of birds. Yellow-green with scarlet tips, and drooping from their stems, they appear in spring to be “leaf hands” with red-painted nails (the meaning of tsuma gaki). In summer, they are held horizontally, rather than downwards, and mature to a deep green. Fall colors are glowing crimsons and reds.
Small, red flowers open with the leaves. They’re considered inconspicuous, but viewed from close-up, I find them to be dainty, charming accents to the showier foliage. Fruits are dry, two-winged samaras, affectionately called helicopters or whirlybirds. The papery wings, each containing a single seed, spin when falling and are carried away by the wind.
‘Tsuma gaki’ is hardy to at least USDA Zone 6 (minimum temperature -10 degrees Fahrenheit), and grows best in moist, fertile, well-drained, acid soils, in part shade or sun (but not reflected heat). Best foliage color develops when well-grown in full sun, which it tolerates in our region. During the Pacific Northwest’s dry summers, consistent irrigation is required.
Like all Japanese maples, ‘Tsuma gaki’ may develop various pest and disease problems. Nonetheless, Japanese maple authorities J. D. Vertrees and Peter Gregory tell us that Japanese maples will usually perform well in our gardens:
Japanese maples generally have fewer pathological problems than many other groups of woody ornamentals. When grown under normal conditions and with good culture, maples are remarkably free of disease and insect problems. The most serious dangers occur in the mass production of young plants, with possible infestations of root weevils and fungal attacks causing damping off. Reasonable soil conditions, good positioning and planting techniques, regular watering, and sound cultural practices, especially regarding pruning and sanitation, will encourage healthy and vigorous growth, thus eliminating or minimizing most problems that can occur with Japanese maples in the garden landscape. [Japanese Maples: The Complete Guide to Selection and Cultivation, 4th Edition, 2009]
Well-grown trees, planted in Pacific Northwest gardens, may experience occasional aphid infestations, but are likely to avoid more serious pest or disease problems.
‘Tsuma gaki’ has been misspelled as ‘Tsuma gari,’ and may also be confused with Acer palmatum ‘Tsuma beni,’ a cultivar that’s similar in name, size, habit, and the color of its spring leaves. Nonetheless, they are distinct selections.
‘Tsuma gaki’ in autumn, its leaves beginning to turn crimson. (photo: Aleks Monk)
Acer palmatum ‘Tsuma gaki’ is a lovely and unusual Japanese maple that should be more widely grown. Its relatively small size makes it suitable for residential gardens, either in deck/patio containers or planted in the ground as a focal point or companion plant. It should be sited prominently where it will be seen in April, despite inclement weather that may keep us from venturing out into the garden. Though not often found at retail nurseries, it’s well worth searching for. Fortunately, very young trees can often be obtained from one or more mail order nurseries specializing in Japanese maples.
We’re fortunate to have two specimens of ‘Tsuma gaki’ planted in the Seattle Japanese Garden. I love their dramatic spring foliage and always take time to admire their beauty during this season of transition and awakening.
Corinne Kennedy is a Garden Guide, frequent contributor to the Seattle Japanese Garden blog, and retired garden designer.