Ume, the Japanese Plum Tree, Prunus mume

The Japanese plum tree, also known as ume, Prunus mume, is in fact an apricot, and originates not from Japan, but rather the mountains of southwestern China. Regardless, this is another iconic tree of Japan, famous not only for its early flowering, often while the snow still falls, but also for its extremely sour fruits which are used liberally in Japanese cuisine – from pickles to sauces, and also as a spice.

This flowering tree is a member of the Armeniaca section of the rather large genus Prunus, which includes cherries, peaches, plums, almonds, and apricots. This last group of fruit trees, the apricots, are best known by the species Prunus armeniaca, the source of the common edible apricot that has been in cultivation for thousands of years. The seven other members of this group are rather obscure with the exception of P. mume, which has been in cultivation in China for over a thousand years, and probably a least a thousand in Japan as well.

Prunus mume in full flower
Prunus mume in full flower in February, Maizuru Koen, Fukuoka, Japan, February 2006.

Prunus mume is a relatively small tree, ranging from 4 to 10 meters in height if left unpruned. It’s flaking bark is typically gray when mature, and with a green tint and smooth when young. Branching is complex and fine. It is a deciduous tree, bearing lanceolate to obovate leaves, typically finely haired, with toothed margins and usually not more than 8 cm in length. Trees are not terribly long lived, perhaps up to a hundred years. The flowers are born singly or at most doubly per fascicle, and open before the leaves by several weeks. Since they flower during cold weather, they can last quite long, up to two weeks or more, before falling.

In simple flowers, the petals are 5 in number, ovate, and about 1 cm long. Multi-petaled types can have many petals and be double that size. Flower color originally was typically white with a pink blush, but nowadays ranges from deep crimson to various shades of pink, pure white, and even green blushed flowers. Depending on latitude and elevation, flowering typically commences from late January into early April, but always well before most trees have begun to break dormancy. The fleshy fruits, known as drupes, range from 2 to 5 cm in diameter, maturing a deep yellow with red-purple blush, and are fully ripe by middle June in Japan.

Prunus mume simple flower
Simple flower varieties of Prunus mume have 5 petals. This white flowered form is closer to the ancestral type.

The precise origins of this species are somewhat unclear given its long history of cultivation, however the likely center of its natural range was where the Yangtze River breaks into its three main constituent sources – the Min, Quingyi, and Dadu Rivers in western Sichuan, near the city of Leshan. It is said to be native to both northern Yunnan and western Sichuan Provinces in forested mountains ranging from 1700 to 3100 meters elevation. That said, it is widely cultivated throughout China, as well as northern Laos, northern Vietnam, Taiwan, Korea as well as Japan. Increasingly, it is is becoming more widely cultivated in Europe and North America in recent decades.

Prunus mume has been selected and cultivated over hundreds of years, and in some cases crossed with similar species, to produce an astounding array of named varieties. In Japan alone, over 500 types have been created, making classification complex and often obscure. Regardless, in Japan most fall within three main groups. They are as follows:

Yabai (野梅系) – These types are the closest to the wild type. Branching tends to be thin and dense, with the smaller branches being somewhat thorny. Flower color typically is white, with pink blushing, particularly on the tips of the buds and inner petals. The leaves are more lanceolate in shape, and are covered in soft, fine hairs.

Hibai (緋梅) – This group includes the forms known as Koubai (紅梅), characterized by their deeply red colored flowers. While these forms tend to produce many smaller flowers that are red in color, some can be white or pink. They are said to be derived from the Yabai group. The pith of the inner wood as well is red in color, as are the the leaf petioles. The leaves are small in size, and similar to the Yabai types. These are commonly grown as garden trees and as bonsai, and less so for their fruit.

Red flowered form of Prunus mume
The deep red flowered forms are known as Hibai or Koubai, and typically grown for their colorful flowers rather than their fruit.

Bungo (豊後) – This group was developed in the historical province of Bungo in present day Kyushu in Oita Prefecture. They are apparently crosses with the closely related P. armeniaca, known as anzu in Japan. Being hybrids, many are not self compatible and have to be out-crossed to create viable offspring. They are said to have low disease resistance, but ironically are also more cold hardy, presumably due to the influence of the colder growing P. armeniaca. For that reason they can be grown even into the Tohoku Region of northern Japan. Flower color and form is variable, from red to white, boasting both single to multi-petaled types, and tend to be later flowering. Branching is relatively thick and sparse. The leaves are usually more ovate than pure P. mume, and hairless. Unfortunately, the fruits tend to have rather fibrous pulp, and for that reason they are not favored for use in cuisine.

With those distinctions aside, there are other characteristics that define the many varieties of this tree. These include: type of branching, flower color, flower size, flower complexity, fruit size and texture, wood color, bud color, flower stance, and so on. Needless to say, differentiations are complex, and as with many things in Japan, subtle. What follows are a few broader examples of this complexity.

Ume flowers in the snow
Ume trees flower in mid to late winter before snow stops falling. Both the buds and flowers of this tree are resistant to moderate frost.

Simple flower types – these can be any color, from red to white, but are consistently 5 petaled, and are closer in form to ancestral types.

Multi-petaled types (called yayae in Japan) – these have thicker looking flowers, with varying numbers of petals depending on the variety. Again, flowers can be various colors, and tend to be rather large in size, commonly twice the size of many simple flower varieties.

Large vs. smaller flower types – flower size can vary considerably regardless of flower complexity. Some, particularly the deep red varieties, can have almost tiny flowers (~1 cm across) while some of the larger ones can approach 6 cm in diameter.

Weeping branched types (called shidare in Japan) – like the weeping cherry trees, one can see lovely examples of weeping ume too. Most commonly the flowers are pink and also multi-petaled. White flowered forms are more uncommon.

Green Flowered types (midorihana) – yes, breeders even have managed to produce flowers with distinctly green tinted blossoms.

Early and late flowering types – some varieties have been selected and bred to flower as early as December, others as late as early April (these are Japan flowering times).

Weeping Prunus mume tree
The weeping branched form of Prunus mume is known as shidare form in Japan.

The subtle variations between size, flower form, color and so on seem almost limitless – enough to intrigue you for a life time, or drive you stark raving mad (or perhaps bored). Trying to keep track of the names of each variety, its characteristics and province is literally a field of study within itself.

The scope of influence this tree has had on Japanese culture is equally impressive. During the Nara Period the plum flower was adopted as a crest (umemon) by several prominent Japanese families, including samurai. Famously, this tree and flower was beloved by Michizane Sugawara of Dazaifu Tenmangu shrine in Kyushu – a politician, scholar, and poet of the Heian Period. To this day his beloved trees adorn the grounds of the shrine, and thousands of students visit annually to get his blessing, since he is to this day worshiped as a god of learning.

The fruits of this tree remain a significant part of the Japanese diet. They are commonly consumed in a salted, pickled form known as umeboshi. These pickles are somewhat of a surprise to the uninitiated, being that they are at once sour in the extreme, as well as very salty. I have watched more than one foreigner choke one up. They are best eaten as a topping for white rice or in a rice ball (onigiri). Eating them as is takes some practice. Pickled ume fruit can have various levels of sweetness, from quite sweet to purely sour, as well as in texture, from crunchy to sticky soft, and even as a slightly moist, candy-like snack.

Beyond pickling them, ume fruit are used to make ume plum vinegar (commonly taken as a health drink), umeshu (a strong liquor made by soaking the unripe fruits in white liquor for months or even years), and also as a flavoring for almost any dish including crackers, candies, dressings and even seaweed.

The flying ume tree
This famous three trunk ume tree at Dazaifu Tenmangu is called tobiume, meaning “flying ume”. The scholar and politician Michizane Suguwara was banished from his position in Kyoto society to the backwaters of Kyushu during the Heian Period. It is said these beloved ume flew from Kyoto to Kyushu to be with him, Dazaifu Tenmangu Shrine, Kyushu, Japan.

The driving force behind all this ume fruit consumption is not only the pleasant sour taste, but the presumed health benefits they are said to have on the human body. The sourness of the fruit belies the presence of a healthy dose of ascorbic acid, common known as vitamin C. They are so acidic that they are literally impossible to eat as is, even if fully ripe, soft and yellow. For that reason they must be processed in some way to mediate their extreme sourness.

Ironically, while eaten as a health food, the unripe fruit also contain toxins that if consumed in large quantities can kill. These poisons are glycosides of hydrocyanic acid, amygdalin and prunasin, commonly found in many Prunus tree leaves and seeds, including common fruit trees such as peaches, plums and apricots. Consumption of these glycosides and the subsequent interaction with gastric acid in the stomach can cause the production of hydrogen cyanide which ultimately leads to convulsions, shortness of breath, paralysis, and eventual death to those who eat too much.

But here’s the rub – the danger rests only with over-consumption of the seeds (which amazingly ARE still eaten by some stubborn people). Moreover, the processing of the fruits, whether unripe or ripe, through the use of alcohol, salt and sun drying, inactivates the enzymes necessary to produce cyanide, hence toxicity levels drop to a minimum. Believe me, eating potato chips is far more dangerous to your health than eating ume based products! All that said, care has to be taken since umeboshi can contain up to 10-20% salt content per weight.

Far from being a dangerous food, thousands of years of eating these fruits in the far east has confirmed that they are not only safe to eat, but also harbor medicinal effects. The known health benefits of vitamin C aside, P. mume fruit have been used in China medicinally for centuries to aid in stomach and intestinal ailments, in controlling intestinal parasites, preventing bleeding (hemostasis), and in suppressing both gram-positive and gram-negative bacteria, as well as pathogenic fungi in vitro. Research in Japan has also indicated that consumption of ume fruit reduces fatigue, increases HDL cholesterol significantly, decrease the chances of developing arteriosclerosis, decreases blood pressure, and stabilizes blood sugar levels.

Unripe ume fruit
The unripe fruits of Prunus mume are a rich source of vitamin C, but are so sour they cannot be eaten as is. They also contain cyanoglycosides that need to be neutralized before consumption.

My own experience with this tree started when I moved into my house in southern Japan 15 years ago. Next to the carport was a well aged, overgrown Prunus mume, though I didn’t know it was that species at the time. In time I found out what it was and realized it had to be pruned soon or it was going to overtake the yard the following season. So, with little knowledge, I hard pruned it soon after it flowered, sometime in mid April. Much to my surprise, it responded by shooting out hundreds of meter long whip-like shoots a month later. Not sure what to do, I in response pruned these back by half.

I learned the hard way that if you want to keep your ume tree to a contained size, it is important to not only know how, but when to prune. I learned that it is best to prune after the fruits have fully matured, that being around late June to early July in my area. If you prune at this time, the tree will not respond by sending up lots of vigorous shoots, but will rather harden off and heal the cut shoots, and then put resources into forming new flower buds on the remaining green wood. This last bit is important when pruning them since cutting back to the older, hardened wood leads not only to completely defoliating the tree (and it subsequently suckering like crazy), but it also prevents the tree from flowering the following season.

For trees that are being pruned to small size, new shoots will begin growing a few weeks after flowering is finished. These normally range from 20-40 cm in length, and start hardening off by the time the fruits are ripening. I usually leave 2-4 buds on each pruned shoot, thus allowing new flower buds to form for next year, as well as containing the overall growth of the tree. In addition, since these trees will produce many new shoots off old wood, it is necessary to routinely remove these to prevent dense branching from forming. P. mume can produce many fruits and this can lead to branches breaking in the wind if shoot length and density is not managed properly.

Here’s a video showing these trees in southern Japan:

For those interested in growing this tree primarily for fruit production, I suggest following methods used to prune other similar trees. In Japan fruit producing trees are typically grown rather flat by constantly cutting out the central lead growth, and encouraging lateral branching. This allows for easier picking since if left unpruned these trees can get quite tall. Again, branch density as well has to be controlled, since heavy fruiting will lead to lower quality and sized fruit.

Regardless, unless you are willing to allow these trees to grow to normal proportions, yearly pruning will be necessary to either keep them smaller, or to optimize fruit production. Luckily, this tree is very responsive to annual pruning, and as stated before, is commonly trained as bonsai.

Interestingly, there is one exception to the pruning technique outline above, that being how to prune the weeping forms. It is common to hard prune weeping ume trees directly after flowering to the old wood, thus causing the tree to sprout many long suckers which naturally hang downward in almost an inverted umbrella shape. This type of pruning leads to massive displays of weeping branches covered in thousands of flowers the following year.

Ripe ume fruit
Ripe ume fruit look very much like typical apricots, but even though full of sugar still are too sour to consume.

Beyond pruning, cultivation is fairly straightforward. Trees should be sited in full sun, preferably in a well drained loam with a moderately acidic reaction. Established trees can endure some drought, but will suffer if not watered. I have found fertilizing unnecessary in the native soils of Japan, but in low nutrient soils, particularly deep sands, you may need to feed them. This is best done in the spring, and perhaps again in summer.

The greatest limitation of this tree is its cold tolerance, which is fairly low. It can be grown reliably in USDA cold hardiness zones 8, 7 and perhaps the warmest parts of zone 6. In colder winter regions it should be sited well, offering as much protection as possible from winter winds in particular. A south facing wall or courtyard may be the best choice in these places. Since flowering starts so early, the risk of it being affected by late cold snaps is another issue, though the flowers and flower buds are able to endure moderate frosts.

Disease issues are fairly minimal, and mostly involve the young tender leaves and shoots. Each year my tree gets infestations of aphids, and at times these can get quite intense, though short lived. If there is a severe outbreak I spray effected branches with strong jets of soapy water which usually seems to do the trick. Since aphids can also spread disease, mass infestations can lead to sooty molds growing on the effected branches as well. I have seen outbreaks of both simultaneously on trees in Japan, and though this rarely hurts them in the long-term, it can effect the growth and health of the developing fruits.

Another common issue with older trees is heart rot. This does not usually kill the tree outright, but it can weaken it significantly, causing the tree to become less stable. Assuming an effected tree is otherwise fairly healthy, it can live with heart rot for many years. The best way to avoid the development of this problem (which is a fungal rot of the inner wood) is maintaining good cultivation practices such as not over pruning trees, not injuring the bark, and otherwise providing good growing conditions – plenty of sun, not overcrowding the tree with other vegetation, and providing healthy levels of nutrients and moisture to the roots.

If you live in a warm temperate climate, or have a protected place in the garden, you might want to try growing Prunus mume yourself. It’s lovely little flowers blooming far in advance of most garden plants are a respite from winter’s cold, and serve as a welcoming harbinger of the spring to come.

The loquat tree, Eriobotrya japonica, the Japanese biwa fruit tree

The loquat tree, Eriobotrya japonica, is an evergreen broad leaf tree or shrub originally native to south-central China, being most famous for its sweet, succulent fruit. Through the years it has been established in subtropical to southern temperate regions across the world and has naturalized in many places. It’s species epithet, japonica, is in truth a misnomer since it was first encountered by a westerner, the botanist Thunberg, in that country. Regardless, the plant has gained notoriety across the globe as an ornamental tree, for its fruit products, as tea (loquat leaf tea) and to a lesser extent, as a medicinal herb.

Eriobotrya japonica is a tree or large shrub of low subtropical mountain forests, attaining a maximum height of about 10 meters. Usually single stemmed, the bark is grey-brown, with smaller branches typically covered in a rusty to grey colored “wool” (a condition known as tomentose).

Loquat Fruits
The ripe fruits of the loquat tree are produced in clusters and typically are bright orange.

The broad crown is densely branched and rounded in form. The tree’s rigid, evergreen leaves are simple, broad, serrated, and deeply veined, each growing from 10-25 centimeters long. New leaves are fully tomentose and light green. They turn dark green and shiny as they age, but remain tomentose on their undersides when mature.

The flowers are borne in loose to tight clusters from late fall into early winter, and are quite aromatic. They are small, no more than 2 centimeters across, with five white petals surrounding a yellow center. The buds as well are tomentose. The flowers are pollinated in the depths of the winter months, and by spring mature into clusters of simple, round and slightly elongated fruits, brilliant orange in color and typically no more than 5 centimeters in length. These as well are have a slight fuzz to the outer skin, but inside are fleshy, juicy and sweet. Loquat seeds, usually numbering 2-4 per fruit (though there can be up to 10), account for much of the fruit’s mass, perhaps up to one third of their total weight.

The loquat is originally native to subtropical forests of southeastern Sichuan and adjacent areas of Hubei Province in south-central China. Since ancient times it has been cultivated over much of southern China, Indochina, Taiwan, and Japan. Readily spreading from seed, it naturalized in these same areas centuries ago, effectively becoming part of the native flora. In more recent years it has been naturalized throughout the world in appropriate climates stretching from India to the Middle East, throughout the Mediterranean region, parts of eastern and southern Africa, the southern USA, throughout Central America and into South America (where it grows in the cooler highlands), Australia, New Zealand, and numerous island chains including Hawaii, Bermuda, and Réunion.

loquat tree new growth
New growth on loquat trees is light green in color and very fuzzy. This growth also contains high levels of toxins and should never be consumed.

This species is considered an invasive weed in eastern Australia (Queensland and New South Wales), throughout the southern USA, New Zealand, South Africa and on many islands throughout the world (for example, Lord Howe Island, Norfolk Island, Easter Island, The Galapagos, Hawaii, Réunion and Tonga).

E. japonica probably was first cultivated for its fruit. Like many other fruit trees, typical wild forms do not usually produce desirable fruit, so selective breeding was needed. Loquat trees are thought to have been cultivated in China for over a thousand years. This tree (known as biwa in Japanese) made its appearance as a cultivated plant during the late Edo Period in Japan (1603-1868), though wild forms with undesirable fruit likely had been brought centuries earlier. Loquats were first cultivated in Europe as early as the 1700’s. It is believed that Chinese immigrants brought the tree to the Hawaiian Islands in the late 1700’s.
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Japanese flowers, ferns, trees and scenery season by season

Japan is a land full of surprises and variety due to its proximity to the tropics, and conversely the boreal zones of the Asian mainland. Habitats are variable as well, largely due to the mountainous nature of this long island chain. In one region alone you can travel from cool temperate rain forest to subtropical lowland hills and islands.

In this video series you get the chance to see Japan’s many faces – the flowering plants, ferns, trees, shrubs, and even animals season by season. What you will find may surprise you. I know it did for me the first time I stepped into its forests, mountains, and hidden valleys. So, enjoy this seasonal tour.

Spring Scenes part I – Spring in southern Japan starts sometime in mid-March with a rush of flowering plants and general growth. Temperatures remain on the cool side most days and nights can very downright cold. By the first week of April the iconic cherry blossoms of this nation are in full swing, as are seemingly countless other species of flowering plants, ferns, and even mosses. Watch the parade of early spring in this video and be amazed.

Spring Scenes part II – The spring series continues in this epic episode. By mid spring wildflowers are peaking and plant growth in general is rampant in southern Japan. You can see a wide array of flowering plants, including wildflowers, orchids, vines, and trees and shrubs, as well as many ferns in full spring growth. This video captures the essence of spring in southern Japan from the finishing of the cherry blossom season in mid April up to late May, just before the monsoon rains of June soak the landscape.

Monsoon Season Scenes – June marks the beginning of the summer monsoon season – a period of seemingly continuous rains. This is a time when a number of flowering plants are at their best, and interestingly several fruits become ripe, notably Japanese plums, hence the Japanese name for this season: the plum rains. Rivers rage, ferns flourish, and myriad insects grow in number and size, creating their signature choral din by this season’s end. In this video you’ll see many common and rare plants, including 11 species of orchid, one of which is critically endangered, Odontochilus hatusimanus. The season ends in mid July with the Yamakasa Festival in Fukuoka City.

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Japanese maple trees at Raizan Sennyoji Daihioin Temple in autumn

Each fall the people of Japan and thousands of visitors to this country look forward to an annual event – the changing of maple leaves to the vibrant colors of autumn. Starting in the north around the last week of September and extending to as late as early December in Kyushu, various Japanese maple varieties put on a show of color that is rivaled only in a few places in the world.

Raizan Sennyoji temple path
These large Japanese cedar trees (Cryptomeria japonica) and close clipped azaleas attest to the beauty of Raizan Sennyoji Temple and its grounds.

Kyushu, despite its southern latitude, harbors some very nice fall leaf viewing from early November up to the first week of December. The best places to look for them are in the remaining natural forests at elevations above 400 meters, particularly along Kyushu’s central mountainous region. Another good option is to look for them at the thousands of shrines and temples that dot the landscape. Even the deepest urban centers are home to these holy places, and almost invariably you can see at least some fall color in the surrounding gardens and woods.

In this pictorial essay the focus is on Raizan Sennyoji Daihioin Temple (hereafter referred to as Raizan Sennyoji) in Fukuoka Prefecture located just southwest of the Fukuoka City metropolitan area. Raizan itself is a 954.5 meter tall summit found along the main ridge line of the Sefuri Mountain group, straddling the border of Saga and Fukuoka Prefectures. The temple is found on its northern flank deep in a valley at around 340 meters elevation near the headwaters of the Raizan River. Among its dozen or so temple buildings is a lovely garden and woods that are home to many maple trees, the subject of this article.

Raizan Sennyoji Temple
The immaculate temple buildings of Raizan Sennyoji are surrounded by beautiful natural and human planted forest. In this picture we can see native forest in the background, a dwarfed Japanese black pine in the foreground, and to the left, the garden's centerpiece - a 400 year old Japanese maple.

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Yoshino cherry tree, Prunus x yedoensis, the famous Japanese cherry blossom

Perhaps the most widely planted of flowering cherry trees in Japan today is the Yoshino cherry, Prunus x yedoensis. Despite its popularity within Japan, and indeed around the world, this Japanese cherry blossom has a history that is relatively brief, and yet the specifics of its origins remain mysterious. Regardless, it is considered one of the most spectacular of flowering temperate trees in cultivation today largely due to its habit of simultaneously opening thosands of showy pink-white blossoms on bare branches – a sight to behold in person.

The Yoshino cherry is a fast growing tree in the first 20 years of its life, then slows down a bit, ultimately reaching heights of 12 meters or a bit more (~40-45 feet), and nearly as much wide. The uniform crown has a spreading, rounded, inverted vase shape with fine branching. Young trees tend to grow upwards, but around 30-40 year old trees begin to spread, with older trees developing attractive hanging branches. The dark reddish-brown bark is marked by prominent lenticels (lens shaped pores in the bark that allow gas exchange). Trees are typically single trunked.

Yoshino cherry blossoms
The Yoshino cherry has abundant pink-white blossoms from late March to mid April.

The simple, broad leaves are borne alternately, are serrated, elliptic to ovate, and up to 15 centimeters long (6 inches). They flush directly after flowering has finished, remaining green until the fall when they turn yellow to orange or orange/red. Flower buds develop during the summer months, remaining dormant until warm days in late March or April trigger them to swell.

Without a doubt this tree’s greatest feature are its lovely pale pink to white blossoms which are borne in generous clusters all along its bare branches. Occasionally they can occur here and there along the main branches as well. Each flower is from 3-3.5 centimeters in diameter, sporting 5 broad petals, first opening pale pink and fading to near white as they mature. These occur in clusters of 5-6, and flower nearly simultaneously on any given tree. The round fruits (known as drupes) quickly ripen, starting out green, then turning red, and finally mature black. They are small (around a centimeter wide), mildly sweet, and not very tasty due to their high acidity (I know, I’ve tried them). Fruit formation is usually fairly modest in this tree.

Being of hybrid origin, Prunus x yedoensis is not found in nature – at least not these days. A little back story first: when botanists started to look at Japanese cherry varieties in a systematic scientific manner, they immediately found themselves in a complex quagmire. Trees that were thought to be species seemed to be possible hybrids, accepted species had different forms (for example upright and weeping), and differences between trees could be very subtle. Add to this mix the fact that Japanese horticulturalists had been selecting and hybridizing cherries for centuries long before the concept of a species (in the western tradition) was even recognized, and you’ve got a mess on your hands. And out of this situation arose the question – what is the Yoshino cherry actually? A species? A natural hybrid? An artificially produced plant?

Yoshino cherry fruits
The fruits, known as drupes, quickly ripen to a black color within just a few weeks. They are sour tasting however due to their high acidity.

We know one thing – the Yoshino cherry was known to be cultivated in Edo (the name for Tokyo during the Edo Period) in an area known as Somei around the middle of the 1800s. Beyond that, things get quite a bit fuzzier. The Somei growers called them yoshinozakura (meaning Yoshino cherry), after a famous cherry covered mountain in Nara Prefecture. This designation was in honor of the mountain only, not implying the origin of the Yoshino cherry. During the 1880s Dr. K. Fujino undertook a study of the cherry trees planted at Tokyo’s famous Ueno Park. He determined that the park contained three distinct species, one of which he called somei-yoshino – a name that has stuck to this very day in Japan. He published his report in 1900 and the following year Dr. J. Matsumura gave the tree its Latin name, Prunus yedoenis. Despite these facts nothing definitive about this tree’s origin was yet known.
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Japanese cherry trees and hanami, the Japanese cherry blossom viewing season

Every spring throughout Japan the most beloved flower of this island nation shows its beauty, and is celebrated with ohanami, literally meaning “blossom viewing”. The flowers in question are of course the world famous flowering cherry trees, known as sakura in Japan. The star of the show is somei-yoshino, known in the west as the Yoshino cherry, Prunus x yedoensis. People gather anywhere they can find a flowering tree large enough to hold an impromptu party under its flowering boughs. They eat, drink, and take in the fine weather of early spring under their favorite national symbol.

The taxonomy of the genus Prunus is problematic at best, containing no less than six subgenera, comprising a wide range of trees. Many are grown for their fruits (plums, apricots, peaches, and of course cherries), and one species, P. dulcis, is famous for its nut, the almond. Some authorities persist in separating these groups into different genera, creating yet more confusion.

Most Prunus that are enjoyed for their flowers are in the subgenus Cerasus, the cherries. The complexity of naming them all is compounded by the extreme variation in flower forms that have been developed over the years. Ironically, most of the cherries enjoyed for their flowers are derived from a relatively few species: Prunus campanulata, P. incisa, P. jamasakura, P. serrulata, P. sargentii, P. spachiana (syn. subhirtella), and P. speciosa (syn. lannesiana). The amazing number of flower forms they can assume however, is astounding – some the result of wild hybridization, and others selected and bred by people, many with their origins lost to time.

What follows is a gallery of photos showing a few of the more common cherry trees in Japan. So with out further comment, here they are…

Hanami, the cherry blossom viewing season

Every spring Japanese people of all ages eagerly await the flowering of Yoshino cherry trees in parks throughout Japan. Ohanami nowadays is simply having a party under the flowering trees, always accompanied by food, and most folks drinking alcoholic beverages – beer, sake, and shouchu, a clear distilled liquor. The celebration pictured above is in Maizuru Koen, Fukuoka City, Kyushu, Japan.

Yoshino cherries along a river
Yoshino cherries along a river

The most commonly planted flowering cherry tree in Japan these days is Prunus x yedoensis, a presumed natural hybrid resulting from the crossing of P. speciosa and P. spachiana f. ascendens. Trees are commonly planted along rivers, streets, and in parks, but only rarely in private yards. Here is a lovely row on the Ino River in Hisayama Town, Fukuoka Prefecture, Kyushu, Japan.

prunus x yedoensis
Somei-Yoshino, the Yoshino cherry

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Moso, Japan’s giant bamboo, Phyllostachys edulis

Japan is home to many iconic plants, for example the Japanese plum tree (Prunus mume), and the red spider lily (Lycoris radiata). The odd thing is that neither of these species is native to Japan, but rather are imports from China. Moso bamboo (Phyllostachys edulis), another Japanese icon, shares their fate. If that weren’t enough, being in truth a very large grass, moso cannot be considered a tree either, despite its arboreal size. Regardless of these facts, moso remains the most important timber bamboo in the world, and has a central role in Japan’s traditional culture, ranging from construction material to food.

Phyllostachys edulis is a large growing bamboo with stems (called culms) routinely attaining heights of 15 meters or more, indeed reports of culms approaching even 30 meters exist in its most favored habitats. Being a “giant” or “timber” bamboo, culm diameter can be impressive, up to 20 cm, but as little as 8 cm in weaker culms.

Moso path
Moso growing along a mountain path in Fukuoka Prefecture, Kyushu, Japan. Impressive stands of this giant bamboo are common place in the warmer parts of Japan.

Like other bamboos, the nodes on the culm are very easy to see, forming a segmented stem that is hollow inside except at the node itself. The culms are not tapered, but rather columnar in structure, only tapering near their apex. The uppermost nodes have one or more side branches that in turn bear the numerous elegant, small leaves. Culms fully mature within two seasons growth and can last up to 12 years.

The paper thin leaves are plentiful and last one growing season, each usually 4-10 cm in length and less than 2 cm in width. In Japan they turn yellow all at once in May and are shed in time with new culm formation. The bright green, new leaves on the old culms grow quickly and are fully developed by June. Branching on the old culms becomes more intricate over time, hence more and more leaves are held by any given culm as they age, thus increasing their beauty and photosynthetic potential.

The culms originate from underground shoots that are born off a highly complex mat of segmented rhizomes that tend to grow fairly shallow in the substrate, typically not more than a half meter deep. On moister sites it is not uncommon to see them growing along the surface of the ground here and there. These rhizomes are stolon-like, extending in all directions, thus making this a “running bamboo” species. The white roots too, are numerous and strong.

New growth shoots break ground in spring once the average air temperature reaches 18-20 C, usually in mid to late April in southern Japan. At first they grow slowly, but once they attain a height of 1 m or so, they rocket into growth, literally. It is well documented that this species is one of the fastest growing plants in the world, having been “clocked” at 1.2 meters of growth in just one day!

Moso leaves
The leaves of Phyllostachys edulis are paper thin, small, and numerous. They hang from graceful arching branches.

The emerging shoots are covered in alternating, hairy dark brown sheaths that are tipped with green, leaf-like projections. These sheaths cover the developing culm as it rockets upward, but just as quickly are shed, starting from the bottom most segments, revealing the new blue-green culm underneath. Remarkably, the culm is fully grown within 5-6 weeks and will begin to harden off, a process that takes more than one growing season. It will never get any taller or thicker however since its anatomy has no means to do this. One has to remember this is indeed a grass, not a woody plant.
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Pinus densiflora, the Japanese red pine

Japan is famous for three pine species, Japanese black pine (Pinus thunbergii), Japanese white pine (Pinus parviflora), and Japanese red pine, (Pinus densiflora). The focus of this article is on the latter species, that like its cousins, is an iconic plant in Japan, used in traditional gardens as a dwarfed tree, but more rarely as a bonsai subject. Moreover, since its wood burns very hot, it makes a great fuel for pottery kilns, and has been used in construction for its durability, strength, and lightness. It is closely related to the Eurasian mainland species, scots pine, Pinus sylvestris.

Pinus densiflora tree
Pinus densiflora is a tall pine species, growing up to 30 or more meters high.

Pinus densiflora is a large coniferous tree growing to 35 meters, but is usually much smaller, not more than 20 meters or so. Specimens found on moister sites with richer soils grow to large sizes and their straight, red barked trunks are unmistakable from a distance. Trees found on cliffs, rock barrens, or dry ridge lines with impoverished soils are far less stately, often standing no more than a few meters tall. The bark is a bright orange-brown color and peels off in paper-like sheets except older bark low on trunks which forms into plates and is silver-gray . The evergreen needles come two per fascicle (or bundle), are a dark green, and up to 12 cm long. Branching is tiered and up swept, forming a distinct, elegant look. Pollen cones appear in early spring, are conical and elongate and orange-yellow in color. The seed cones start at the same time and are yellow to purple in color. These female cones mature by fall and are small, not more than 6 cm long, occurring alone or in clusters. The winged seeds are about 1.5 cm long.

This is a widespread tree in Japan found from northern Honshu and southward to Kyushu and Shikoku. It is most commonly seen growing in low mountains and hillsides, but can be found up to 2500 meters elevation in parts of its range. Its typical habitat are dry ridge lines with poor soils that have been subject to recent disturbance as this is a colonizing species, and is usually one of the first trees to seed in after a fire or other disturbance. For this reason, you often see near pure stands of it here and there, no doubt due to forest fire. I’ve noticed it also colonizes abandoned mines on shear cliffs alongside other weedy pioneer tree species such as Mallotus japonicus and Rhus sylvestris. It is believed that in times past it was much more uncommon a plant since disturbance due to fire was very limited prior to human habitation. It is one of the few trees than can withstand growing in windswept rock barrens.

Pinus densiflora bark
The younger bark is a brilliant orange-brown color, but older bark found lower on trunks is silver-gray and forms plates.

Where this species is found in mixed stands with Japanese black pine, Pinus thunbergii, the unusual hybrid called akakuromatsu (red-black pine) sometimes results (known under the Latin name. P. x densi-thunbergii). These hybrids have the red bark of P. densiflora while retaining the darker, more stout needles of P. thunbergii.
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Tsubaki, Camellia japonica

A member of the tea family, Theaceae, Camellia japonica is one of Japan’s most famous flowering trees. Known as tsubaki in Japanese, this plant is a common small tree throughout the warmer regions of the Japanese archipelago. In recent times it has been widely cultivated as a garden plant, but in the not so distant past the oil derived from its bulbous fruits was used as a multipurpose product, serving as a food, a hair and skin treatment, as well as a machine oil.

Camellia japonica tree
Camellia japonica is most commonly seen as a sub canopy tree, but occasionally specimens grow in open, sunny habitats such as this ridge line forest. Homanzan, Fukuoka Prefecture, Kyushu, Japan.

Camellia japonica in nature is an evergreen subcanopy tree, commonly 3 to 6 meters tall, with occasional specimens being quite a bit higher than that. The tallest on record is 18 meters (that’s almost 60 feet!). I’ve seen many in the 10-12 meter range with trunk diameters approaching 60 centimeters in really large trees. The bark is an even gray color and very smooth.

The wide, slightly serrated ovate leaves are borne in an alternating pattern and typically measure between 5-10 centimeters long and 3-6 centimeters wide, ending in a pointed tip. They usually are a deep green color on their dorsal surface and a bit lighter underneath. The dorsal surface is also very glossy, adding to the visual appeal of this plant. The soft, new leaves are most actively in growth after flowering in the spring. Flower buds are formed in the fall and over winter until opening in late winter or early spring.

The flower petals of wild plants are typically deep red, though pure white forms have been reported. They are joined at their bases such that when the flower falls off, it is intact (we’ll see why that is important later). The prominent cluster of stamens are a yellow orange color while the three lobed pistal is “lost’ in them. Wild flowering types commonly boast only a handful of broad petals and the blossoms tend to remain rather cupped compared to many of the cultivated varieties. The fruits are nearly perfectly round before opening, starting out apple green and maturing into a purple-red. They open in three sections (called locules), each containing anywhere from 1-2 large brown seeds.

Flowering season in southern Japan starts in winter, usually not before January, peaks around March, and trails off in late April. At higher elevations flowers can persist even into mid May. Flowering is later further north, and can last into mid spring, however, it is not uncommon to see this tree in flower when snow is still falling. This cold weather flowering habit has earned it one common name, rose of winter. Due to the relative lack of insects in winter, the flowers are often pollinated by small birds, in particular the Japanese white-eye, Zosterops japonica.

Camellia japonica flower
The flower of the common wild type of Camellia japonica is much simpler than most cultivated forms, but lovely and elegant.

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A beautiful laurel tree of Japan, Neolitsea sericea

Japan’s southern and coastal regions are home to the northernmost occurring examples of Asia’s laurel forests. Here the climax forest community is dominated by trees in the laurel family (Lauraceae), evergreen members of the beech family (Fagaceae), as well as the tea family (Theaceae). Neolitsea sericea is a common laurel tree found in these temperate evergreen forests. It is a remarkable tree in many respects, especially its foliage, as you will see.

Neolistea sericea flowers
Neolitsea sericea flowers in the autumn just before the cold weather hits.

Neolitsea sericea is a moderate sized broad leaf evergreen tree, attaining a maximum height of 10-15 meters. Unimpeded, it forms a rounded crown, but rarely is it seen outside a forest setting in Japan where it must compete for light and therefore usually has a more ranging form. Trunks usually don’t exceed 60 cm in diameter and the relatively smooth bark is brown.

Its mature leaves are lanceolate and oblong, 8-18 cm in length, and dark green with 3 prominent lighter green veins along their length. When young they form in a whorl and hang down almost vertically. At this stage they are covered in an extremely shiny, soft velvet like hair that in truth is a muddy yellow green, but gives the impression of brilliant silver in the spring sun. To the touch they are soft, like velvet or silk.

Within a few weeks these hairs shorten to a light pubescence as the leaves mature and take on an extraordinary dark pink to reddish purple coloration throughout.  The prominent veins of the leaves are almost white at this stage in development and the leaves are more staggered along the newly forming twig in an alternating pattern.  By early summer they mature, losing the pink color and all pubescence.  What is left is a stiff, glaucous mature leaf.  The underside of the mature leaf is a nearly white/green, hence its Japanese name shirodamo, meaning “white ash” – a reference also to the Japanese ash tree, Fraxinus mandshurica v. japonica.

In mid fall, just before colder temperatures hit, buds along the newly formed leaf axes open into masses of yellow green flowers.  These form into berries over the winter months, remaining green throughout the following growing season only to turn deep crimson the following fall.  They are very conspicuous and remain on the tree most of the following winter.  N. sericea is dioecious, with male and female trees.  Since only the females bear fruit, that must be considered if you want to have fruiting trees.

Neolistea sericea new leaves
The newly forming leaves of Neolitsea sericea grow in whorls and are covered in soft yellow-green hairs.

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