We owe countless and very valuable cultivars for the garden to the Japanese flowering cherry (Prunus serrulata). The flowering shrub from the rose family (Rosaceae) originates from Japan, but is also found in parts of China and Korea. The Japanese cherry blossom is firmly anchored in Japanese culture, as the cherry blossom festival (“hanami”) is traditionally celebrated at the time of blossoming. In addition, the cherry blossom (“sakura”) has been a symbol of simple and pure beauty there for centuries.
In its natural habitat, the Japanese flowering cherry grows into a tree up to 25 meters high. Its bark is very decorative: smooth and dark brown with a reddish tinge. The young twigs appear bare at first. The growth forms and heights of the individual cultivars differ greatly from the wild species and are sometimes narrow and upright, sometimes columnar, roundish or conical. Some also have an arching overhanging crown.
The leaves of the deciduous Japanese flowering cherry are ovate to lanceolate. The serrated leaf edge is alluded to in the tree’s botanical name: “serrulata” is the Latin word for “finely serrated”.
In bloom from April to May, Japanese flowering cherry is covered all over with semi-double to double flowers surrounded by small green to red bracts. The funnel-shaped flower cups are arranged in umbels. The flower color is mostly pink, but can also be whitish or yellowish in color.
Alley of Japanese flowering cherry
In Japan there are whole avenues of Japanese flowering cherry, which of course are a stunning sight at flowering time.
After flowering, from May to July, the small black spherical to ovoid drupes of Prunus serrulata ripen. They contain the seeds.
The Japanese flowering cherry develops its full splendor only in full sun locations. Lack of light does not suit it.
Prunus serrulata does well in most sandy-loamy garden soils in this country: ideally, they are rich in humus and nutrients, slightly calcareous and fresh to moist. Only heavy soils should be deeply loosened and enriched with sand or gravel for better drainage before planting.
Japanese flowering cherry is best planted in the fall. In the nurseries you have to search a little for the wild species, but from time to time it is offered as balled or containerized. The planting hole should be at least twice the circumference of the root ball. The soil must be properly trampled after refilling and watered thoroughly.
Like most ornamental cherries, Prunus serrulata is very low maintenance. Watering by hand is only necessary in the first year of growth or during prolonged drought. Watering is facilitated by a watering rim that is drawn around the trunk. A layer of mulch reduces the evaporation rate in the sunny location and keeps the moisture in the soil.
Regular pruning is not necessary for Japanese flowering cherry – the first three to five years do not cut it at all. For older specimens, small corrective pruning or thinning can be done in the spring.
The Far Eastern flowering shrub has no problems with our climate. It is sufficiently hardy even for the winter months.
Because of its stately size, the Japanese flowering cherry is better planted only in large gardens or park-like areas. In any case, it is necessary to maintain a sufficient distance from the surrounding houses. However, if you can, Prunus serrulata will bring an incomparable flowering wonder into your garden, which is sure to attract all attention at flowering time.
In the normal home garden, the species plays a rather minor role. However, the varieties are of great horticultural interest, which is reflected in the wide range. Probably the best known and most popular garden form is the clove cherry (Prunus serrulata ‘Kanzan’), which, with a maximum growth height of twelve meters, remains considerably smaller, but because of its spreading crown also only finds a place in large gardens. As a house tree for small gardens and front yards, the columnar-growing Japanese columnar cherry (Prunus serrulata ‘Amanogawa’) is particularly suitable.
The hanging clove cherry (Prunus serrulata ‘Kiku-shidare-zakura’), on the other hand, delights with a spreading habit and old pink flowers. The variety grows between four and seven meters high. In addition to numerous other varieties such as ‘Hokusai’, ‘Shiro-fugen’ or ‘Shirotae’ (also known as ‘Mount fuji’), the Chinese Mountain Cherry (Prunus serrulata var. hupehensis) is also worth mentioning. The variety convinces with decorative foliage, which shows a reddish-brown coloration in budding. Its buds are initially pink, the later flowers pure white.
For propagation, seedlings are grown and then grafted – a demanding task that is hardly feasible for amateurs.
Diseases and pests
The only plant disease that can be problematic with Japanese flowering cherry is Monilia disease (spike drought), which can occur following flowering. So check the shoots in June for dying tips and remove affected branches promptly. By the way, the variety ‘Kanzan’ is not affected by it.
Pruning Japanese cherry – you should know.
Basically, the Japanese ornamental cherry is very easy to care for. However, a sunny location and regular pruning should be considered. This is what you should keep in mind when pruning:
- Prune the ornamental cherry after flowering in spring. This way you can easily see where new shoots are forming. Pruning is still possible in June or July. Give the Japanese ornamental cherry about three to four years before you prune it for the first time.
- Ideally, prune the Japanese ornamental cherry every one to two years. Complete pruning is not necessary for most species. However, you should prune small varieties such as “Prunus kurilensis Brilliant” or “Prunus fruticosa Globosa” annually.
- It is usually sufficient to simply thin out the crown of the tree to allow light and air to reach the foliage. In doing so, cut off branches that interfere with the natural character of the growth habit. Also, remove any diseased or bent branches.
- Be sure to cut older shoots vertically close to the heel and avoid damaging young shoots. Trim branches that have grown too long above the bud of a new shoot.
- Depending on the size of the ornamental cherry, branch saws, loppers or secateurs are suitable. In any case, be sure to use sharp tools, which you disinfect before cutting. The Japanese ornamental cherry is sensitive to bruising.
- Apply wound sealant to the cuts after pruning. Afterwards, dispose of the cut plant residues in the green waste.
- Too many branches drain the life forces of the Japanese ornamental cherry. If you notice slowed growth, you should give the plant a rejuvenating pruning. Reduced flower growth also indicates that the plant has already grown too quickly or densely. If necessary, perform this “vitalizing pruning” additionally in October.
- Species and life span of the Japanese ornamental cherry
- The Japanese ornamental cherry belongs to the rose family (“Rosaceae”) or to the genus Prunus. There are numerous varieties and species, which differ in shape, flowering and size. The spectrum ranges from trees up to five meters high to shrubs with hanging branches and columnar shrubs that can also grow in pots.
The best-known varieties include “Prunus subhirtella” (spring cherry), “Prunus serrulata” (clove cherry) or “Schmittii” (mirror bark cherry). Pink winter cherry “Prunus subhirtella Autumnalis Rosea” is also widely used.
With regular pruning, the robust ornamental shrub will bloom for several years to decades, depending on the genus.
Flowers and fruits of the Japanese ornamental cherry.
The tree species is famous not because of its fruits, but because of its pink flowers. They appear in spring from the beginning of April to the end of May.
- In summer, the leaves of the Japanese cherry turn green. In autumn, the leaves have a slightly reddish shimmer. Depending on the variety, the leaves are about five to ten centimeters long and either pointed or serrated.
- It is “not good to eat cherries” with the Japanese ornamental shrub. The plant rarely bears fruit. If it does, however, they resemble dark red to black cherries. However, the fruits of the ornamental cherry are not edible.
- Because of their rapid growth and spreading crown, Japanese ornamental cherry trees are best planted in a spacious location where the tree can stand freely. This is the best way to show off the flowers. Also make sure that the soil is chalky and well-drained. A normal garden soil is usually quite sufficient.
- A sunny to maximum partial shade location is ideal for the colorful blooms of the Japanese ornamental cherry.
While the fragrant flowers of the wild form are swarmed by numerous insects, especially honeybees, wild bees and hoverflies, the double flowers of some varieties block the way to the nectar. They are not quite as popular with us as they are with the Asian honeybees Apis cerana and the Andrena species there, but they are still popular. They provide significantly higher yields. It will rarely be possible to harvest many fruits here, especially since many cultivars have sterile untransformed fruit leaves, such as the varieties ‘Fugenzo’ and ‘Ichiyo’.
The black and green aphids mainly target the extrafloral nectaries on the petioles, which secrete sweet sap even without deep holes. The honeydew on the aphids’ hindquarters attracts ants, which in return keep pests away from their flock and their food plant. So evolution has definitely come up with something for the unusual location of the nectar glands.
Things to know
Hanami and the Japanese cherry blossom
The exuberant flowering of the Japanese ornamental cherry is unique – no wonder that hanami, the time of cherry blossom in Japan, has been celebrated with a festival since time immemorial. The short but splendid blossom is considered a symbol of the transient life, among others for the young samurai, who wished for a glorious death in battle in the blossom of their life. Moreover, with their delicate fragrance and simple beauty, they symbolize purity and simplicity – important elements of Japanese culture.
The popularity probably came about late: today botanists assume that the ornamental cherry, originally native to China and Korea, was first introduced to Japan and spread rapidly there thanks to its popularity. It is from here that most of the cultivated varieties available in the specialist garden trade originate. Some of them also contain substantial proportions of Oshima cherry (Prunus speciosa or Prunus serrulata f. albida), which grows endemically in Japan.
Medicinal uses of Japanese ornamental cherry
In traditional folk medicine, the fruits of the ornamental cherry are used for heart diseases such as heart failure with edema, gout and toothache. The inconspicuous cherries have antioxidant, antibacterial and virucidal effects. Cherry blossom essential oil is used in aromatherapy as well as in the perfume industry; it has relaxing and stress-relieving effects.
The wild form of the mahogany cherry is rarely offered and even more rarely planted. It is much more common to find one of the numerous cultivars that differ in growth habit and height. Some of them have semi-double or double flowers, which are better avoided out of consideration for the hungry insect world – they are more decorative than the simply designed flowers, but offer less food due to the transformation of stamens into additional petals.
Japanese cherry in the garden
The Japanese ornamental cherry has no special requirements for the soil; however, it should be deep, well-drained, fresh and moderately to abundantly nutritious, preferably with a neutral to alkaline pH and sandy or loamy, preferably with lime underneath. Cold, wet and highly acidic soils are unsuitable for the plants. The location should be warm and sunny to semi-shady. Most varieties are absolutely hardy down to -26 °C.
In order for the beautiful crown of the Japanese cherry to develop optimally, you should cut it as little as possible – then it grows most beautifully. Only old dead branches can be removed at any time. Should it ever become too large: It doesn’t mind a heavy pruning, it is considered to be well tolerant of pruning.
It should be noted that some mahogany cherries, especially the numerous species, are often or almost exclusively grafted onto a particularly vigorous rootstock to make them even more resistant. It can happen that the rootstock sprouts a cheeky rice, which can be easily recognized by its different bark and flowers. You should remove these wild shoots of the grafting base as soon as possible, because they take a lot of strength away from the scion and could overgrow it in time.
Propagation of the numerous varieties of Japanese ornamental cherry is only possible vegetatively – they are already grafted onto a vigorous relative in the nursery. In most cases, this is a native bird cherry (Prunus avium) Therefore, one will usually resort to an ornamental cherry from the garden specialty store if one wants to bring such a magnificent ornamental shrub into one’s garden. Cuttings also usually grow reasonably reliably, but they are often not quite as hardy as the grafted forms.
Apart from that, no one is stopping you from trying to sow the seeds, if your ornamental cherry sets any at all – you might be in for a surprise. Since you never know who has played the role of the father as a seed donor, anything can happen. Tip: The seeds are cold germinators and need a cold period to germinate reliably.
Ornamental trees are a regular feature in parks and green spaces. With its pretty shiny bark and exuberant blooms, the Japanese ornamental cherry does best in the home garden as a specimen or a few specimens in a small group. This is the best way to show it off to its best advantage. Small varieties are also suitable for hedges and rock gardens or even as a container plant for balcony and terrace.
Remarkable is their resistance to the urban climate – smoke gases are not able to harm the pretty bushes. Japanese ornamental cherries are just as indestructible as bonsai – actually no wonder that this ornamental tree, so popular in Japan, also receives attention for this purpose to this day and blooms no less lushly in mini pots.
On the whole, the mahogany cherry is quite hardy and has little to do with pests and diseases. You will have to put up with aphids, they often appear in masses especially on the fresh shoots and leaves – and also on the flowers. If it calms you down: As a rule, they cannot do much harm to the beautiful Japanese plant. Woolly aphids mostly occur when the plant is under glass, and most natural pests such as beetles, cicadas and caterpillars are unknown in our latitudes. Lucky for the Japanese cherry.
What is Japanese cherry?
Japanese ornamental cherry, Japanese flowering cherry, Grannenkische or mahogany cherry (Prunus serrulata) grows as a small tree or large shrub and is a pretty and at the same time undemanding flowering and ornamental shrub for the garden. It is native, as the name suggests, to the forests and shrublands of East Asia, especially parts of Russia, as well as China, Korea and Japan. Like all species of the genus Prunus, it belongs to the rose family (Rosaceae).
A striking feature of the three to twelve meter tall ornamental cherry is the smooth, mahogany or maroon bark with horizontal bands of corky warts, which has also earned it the European name Mahogany Cherry. The shrubs or trees themselves are broad-crowned or columnar, with sometimes overhanging branches. Many varieties also remain much smaller than the wild form.
The alternate leaves on the branches have a glabrous petiole 1-2 centimeters long and an ovate-elliptic or obovate-elliptic leaf blade. They grow to be 5-13 centimeters long and 2-7 centimeters wide, with a rounded to wedge-shaped base and a small tip. The leaf margin is single to double finely serrated – nothing else means the species name serratula in Latin. At the base of the petiole are two linear-shaped stipules with glandular-fringed margins, its upper surface harbors one to three extrafloral nectaries. Towards the end of the year, the leaves shine in a red and yellow autumn color.
The main flowering season is April and May; then, together with the leaf shoots, masses of partly frilly flowers appear, which completely cover the branches, but unfortunately have a limited life span. Most of them fall off after only a few days, so that the flowering splendor is quickly over and whole carpets of pink petals cover the ground below the cherry trees.
The individual flowers are pink to white, darker pink in some cultivars, and sometimes double, and stand in twos or threes, rarely up to five, on a common short inflorescence stem with small brown-red bud scales and brown-colored bracts. As in all rosaceous plants, the flowers are hermaphroditic, stellate, and pentate with a double perianth, with lanceolate sepals five millimeters long and free entire-margined and obovate petals. Inside the flowers are 30-40 stamens and the ovary with glabrous pistil. The latter, after pollination, develops into a globular drupe, in Japanese sakuranbo, 8-10 millimeters in diameter; they turn from green to dark red to almost black as they ripen and contain a single small stone seed with the brownish seed. The marginally present pulp tastes distinctly bitter and is hardly edible raw. In our latitudes, the cherries are not only rarely formed, they also ripen rather rarely.