I think that I shall never see A poem lovely as a tree. --Joyce Kilmer
Many of us remember this poem from school days. Although poet Joyce Kilmer doesn’t mention it in "Trees," his most famous work, certain trees hold not just a lovely vision, but also a lovely aroma. You may not be familiar with the Katsura tree now, because it is not as popular as some other landscaping trees, but once you come to know it and its distinctive, delicious, spicy-sweet odor, you may just find it's the perfect tree for your residential landscaping needs.
You don't get caramels from it, but some think the wonderful Katsura tree smells like caramel or cotton candy when it loses its leaves in the fall. Besides being wonderful to smell in the fall, the Katsura sports a lovely blend of orange-, raspberry- and apricot-colored leaves. The Katsura is no slouch in other seasons, either. In the spring Katsura has reddish-purple new growth, in summer it sports heart-shaped blue-green leaves and in winter the gray, slightly exfoliating bark lends interest. This lovely shade tree is hardy throughout most of the United States and deserves to be planted more frequently.
The Katsura is native to Japan and eastern Asia and is widely used as a landscape tree in those areas. The Latin name, Cercidiphyllum japonicum, refers to the leaves, which look like one of our native trees, the Redbud. Katsura leaves are blue-green, lighter below, and heart-shaped. In the spring the leaves emerge tinged with purple or red, and some trees hold a trace of color in their leaves throughout the summer.
Katsura blooms in early spring.The flowers are not showy, and they are produced on separate male and female plants. On the female Katsura, the flowers turn into clusters of small pods, which open and release winged seeds in the fall. The pods and the seeds are not very noticeable and do not make a mess.
The shape of the Katsura tree is variable. Some are multistemmed with broad, flat crowns and others are single\-stemmed and more pyramidal in shape. There are also a few weeping varieties of Katsura. The trunks of young Katsura trees are thin-barked. This becomes thicker, furrowed and lightly peeling as the tree ages. Katsura trees have a distinct root flare. Some roots are developed right at the surface of the soil and can get quite large with time. These roots lend an architectural appeal to the Katsura form.
Katsura trees can mature to 40 feet or more. There is another species, Cercidiphyllum magnificum, even less frequently seen outside of Japan, that is smaller in height but has larger leaves.
Growing Katsura trees
Katsura trees are hardy from Zones 4 to 8. In the North they should be in full sun. In the South they will grow in light shade also. Katsura trees like moist, fertile, loamy soil. Katsura does well where the water table is high. They tolerate a wide range of soil pH.
The roots are shallow and the tree must be kept well-watered, especially when getting established. The biggest problem with the Katsura tree is they are a little tricky to establish. Once they settle in a place to their liking, however, they grow rapidly.
Smaller trees transplant the best, and they should be planted when dormant in the early spring. Keep them well-watered. If the Katsura experiences drought conditions, it will lose it's leaves. Usually the leaves will be replaced when water is again available, but if this happens frequently, you will probably lose the tree.
The thin bark of young Katsura trees are prone to sunscald and splitting in the winter. Protect young trees with tree wrap or shade on the south and west sides during the winter. Tree tubes may help small Katsura establish easier.
Since the Katsura has roots close to the surface, deep mulch should be avoided. You can plant under the tree if care is taken not to cut too many roots. Before planting Katsura, remember that the tree may form surface roots and these might make mowing difficult.
After the first year, an application of 10-10-10 or other tree fertilizer in early spring may help get the Katsura tree off to a good start. Katsura trees have few insect pests or disease problems and rarely require pruning.
The caramel, cotton candy or brown sugar smell (depending on your nose) comes in the fall, when the Katsura tree is losing its leaves. Most people find it quite pleasant. It is strongest in warm, sunny weather and can perfume the whole yard. The aroma is especially noticeable on those autumn days when the air is dry; the Katsura leaves produce the odor when they fall from the tree.
Two weeping forms exist in Katsura. Pendulum is upright, with a strong trunk and weeping branches. It is also sold as Morioka Weeping. Another type has no central trunk; it is more like a weeping bush. Tidal Wave is one variety name of this type.
Heronswood Globe is a compact, rounded variety, seldom over 20 feet high, that is good for small yards. Several varieties of Katsura exist that have excellent fall leaf color. Most Katsura have variable fall color, with each tree having a somewhat different blend. Strawberry Katsura has pink-red fall color and touches of pink in the spring leaf color. Raspberry Katsura has wine-red fall color.
Katsura makes an excellent shade or specimen tree. Once established, Katsura is a no-muss, no-fuss tree with great structure for the landscape. It is also a good choice as a street tree, where it could possibly be a good replacement for ash trees dying from Emerald Ash Borer.
As they are an excellent choice for residential use, Katsura trees are often used to line driveways or other places where they stand out in a landscape design. Katsura trees are also a good choice for many commercial uses as well, especially large, open areas such as parks and golf courses. You can find them in many nurseries, and also in arboreta such as the New York Botanical Garden, since the Katsura was introduced to American nurseries in 1865.
While the Katsura is related to an extinct tree that lived in North America before the last Ice Age about 10,000 years ago, the modern Katsura came to the United States when seeds were sent from Japan by Thomas Hogg Jr. to his brother horticulturist in New York. Unfortunately, the Katsura was not the only plant introduced to the United States by Hogg. He also sent the notorious kudzu vine, an invasive plant which has caused problems wherever it has been introduced throughout the world.
Why Grow Katsura?
Katsura are hardy, resistant to damage by insects and disease, so there are fewer problems to worry about than with other trees. People enjoy the way Katsura trees look and smell, and they are easy to fit into various types of landscape design.
Because each tree is either male or female (with different types of flowers on each), you’ll need both male and female trees if you want to have seeds. Katsura are ornamental; that is, neither the seeds nor flowers or other parts of the tree have any medicinal value. The wood from the Katsura is used to make various types of furniture and boxes, and is especially known for being used to make boards for the famous ancient game of Go.