When it comes to plants that I seem destined never to acquire, the koshiabura tree Chengiopanax sciadophylloides is surely at the top of the list. This small tree in the ginseng family Araliaceae is an endemic Japanese species which is revered as a spring vegetable. Koshiabura grows along the full length of Japan from the mountains of Hokkaido to Kyushu in the south. It likes to grow along sunny woodland edges on mountain slopes.
A lone koshiabura tree growing at the US National Arboretum in Washington DC.
Wild vegetables in Japan are referred to as “sansai”, which translates literally as “mountain vegetables”. The koshiabura tree is so revered as a wild food in Japan that it has earned itself the title of “queen of sansai”. (The “king of sansai” is the closely related Aralia elata) The young shoots of the koshiabura tree are harvested in the spring and are boiled to serve in a variety of dishes, or fried up raw as vegetable tempura. They are grown commercially on a small scale and can even be found in Japanese grocery stores when in season. It is said that koshiabura trees growing along mountain paths are often stunted due to excessive harvesting of the shoots!
Koshiabura shoots ready to cook.
The young shoots of many trees and shrubs in the ginseng family Araliaceae are eaten as sansai in Japan. These include Aralia elata, Kalopanax septemlobus, a few Eleutherococcus species, Gamblea innovans, and finally Chengiopanax sciadophylloides. There are two attributes which make koshiabura especially desirable among this group. First of all, unlike most of the other species, which are viciously thorny, koshiabura is completely free of thorns. Second, the plant has a milder flavor than most other Araliaceae species, free of the harsh bitterness found in some of the species listed above. In a 2004 paper, David Brussell, an American ecology professor living in Japan, stated that koshiabura shoots were his favorite of the many sansai he tried during his stay, describing them as “delicious”.
The smooth gray bark of the tree – no thorns!The young leaf buds in March, too early to harvest.
Of course, I can’t personally comment on the flavor of the plant, as I’ve been completely unable to source one! As far as I know, the only koshiabura tree growing in the United States at present is a single small specimen growing in the Asian Collections at the US National Arboretum in Washington, DC. Unfortunately the species is dioecious, with separate male and female plants, so the tree in Washington DC will never produce seed for further propagation. Readers in the UK can get this plant from Crûg Farm in Wales. As for the rest of us, we’ll have to import seeds or plants directly from Japan – a difficult process any way you look at it. Some research has shown that the koshiabura tree can accumulate manganese from the soil into its leaves, potentially reaching hazardous levels. Sometimes I’ll use this fact to make myself feel better about not being able to obtain this plant!
The large leaves have five leaflets on a long petiole. This leaf is just starting to show its yellow fall color.
The name “koshiabura” might sound odd to English speakers, but the tree has no English common name as it is only found in Japan. “Koshiabura” translates to “strained oil” in Japanese – a reference to one of the historical uses of the tree. By straining the resin found in the tree, a prized lacquer called “gonzetsu” is obtained. This lacquer was famous among Japanese and Chinese nobility for its glossy golden color and high durability, actually becoming harder when exposed to ultraviolet light. Koshiabura and the closely related Gamblea innovans were used for this purpose until the Heian period (794 to 1185 CE) when it was discovered that the faster-growing Toxicodendron vernicifluum could be used instead.
The author with what is likely the only koshiabura tree in the United States.
There are a lot of unknowns when it comes to the koshiabura tree. How large will it grow outside of its native range? Japanese sources list it as growing from 5 to 18 meters tall. What are its actual hardiness limits? The Arnold Arboretum in Boston, Massachusetts has attempted to grow it several times, but none of the trees have survived to the present. There is also a Chinese species, Chengiopanax fargesii, which is even more obscure but is likely to have all of the same useful properties. I hope to one day grow one of these obscure edible trees in my own garden so that I can answer some of these questions for myself! If you are able to get your hands on this species, by all means please let me know!
Back in the spring of 2022 I was trying to solve a garden problem that had been plaguing me for some time. One edge of my front lawn, where I wanted to grow a food forest, connected seamlessly with my neighbor’s front lawn. The shared border of our properties is roughly 30 feet (9 m) long and highly visible to passersby on the sidewalk and street. If I wanted to grow a garden in this spot, I would need a physical barrier to prevent the neighbors from mowing down or walking on my valuable plants. In addition, I wanted to make sure that mulch I put down in this area didn’t migrate onto my neighbor’s property. A fence would be the obvious solution to this problem, but I thought it would be too mundane a solution for such a highly visible part of the yard. I wanted my yard to inspire others to garden, and this part of the yard would be the first thing people see when coming down the street.
The problem area
So I decided that a small ornamental hedge would be the ideal solution. The hedge should be under 4 feet (1.2 m) in height so that I could see over it while backing out of the driveway, and should be under 2 feet (0.6 m) in width so that it wouldn’t take up too much of my limited gardening space. Of course, since I was planning on growing a food forest, I was also looking for a plant that was edible or useful in some way. The hedge in question would have to meet all of these requirements on top of being well-adapted to the conditions of the site: a dry and sunny location in USDA zone 6b.
Traditional boxwood hedges – pretty but not terribly useful.
As I began my research, the first plant that came to mind was the Japanese flowering quince, Chaenomeles japonica. This is a short Asian shrub in the rose family with attractive flowers and small edible fruits. It tops out at around 3 feet (1 m) in height – perfect – but tends to have a messy habit and naturally grows twice as wide as tall. This means it would require frequent pruning to keep the hedge looking tidy and its width in check. As I thought about it more, I realized that because this species flowers on the prior year’s wood, routine pruning of the hedge would also result in a reduction in flowers and fruits. In this way maintaining the plant as a hedge runs counter to its main uses – fruiting and flowering, making it a poor fit.
Japanese flowering quince (Chaenomeles japonica) in bloom at the Arnold Arboretum.
It was at this point that I had a realization. If I could find a hedging plant that had edible leaves, then I could combine the pruning and harvesting into a single action. Growing the plant as a hedge wouldn’t be a negative, but a great way to keep the leaves within reach! Instead of composting the clippings, I could actually eat them, and additional pruning would only stimulate the plant to produce more tender young leaves for me to harvest. If a plant like this existed, it would have a magical synergy between ornamental and edible qualities.
A hedge of chaya (Cnidoscolus aconitifolius) growing at ECHO (Educational Concerns for Hunger Organization). Photo from Eric Toensmeier.
Now it may sound odd to the average Westerner to eat the leaves of a shrub, but I had heard about it being done with a few different species in the tropics, such as chaya (Cnidoscolus aconitifolius) and katuk (Breynia androgyna). Was there a cold-hardy plant that could fill that same role in my New England garden? As I do whenever I have questions of this kind, I consulted the Plants for a Future database. I ran a search for all shrubs with edible leaves that could grow in my conditions and began delving into the data.
An excerpt from the PFAF page for fiveleaf aralia, Eleutherococcus sieboldianus
As I was poring over the data, one plant in particular stood out to me: fiveleaf aralia – Eleutherococcus sieboldianus. It had reputable citations for the edibility and good flavor of the leaves, was fully hardy, (down to zone 4!) and was even marked as a species suitable for growing as a hedge. Fiveleaf aralia is a woody member of the ginseng family, which contains a number of other shrubs and perennials with long histories of edible and medicinal use. This gave me some confidence that it was at least safe to consume. Its listed height and width of around 8 feet (2.4 m) however seemed at odds with its recommendation as a hedging plant. All of the photos I found of the plant online were of a large sprawling shrub.
Fiveleaf aralia growing in a woodland setting at Hortus Arboretum in upstate NY.
So I tried to find examples of this plant being grown as a hedge. In doing so I came across “Experiments with Hedges”, a 1931 publication by famous landscape architect Frank A. Waugh. In this paper Waugh details his experiments with various plant species as hedges, including fiveleaf aralia under its old Latin name Acanthopanax pentaphyllum. Waugh says of the plant: “This makes an excellent hedge if conscientiously pruned. The example in this experiment stands 3½ – 4 feet high and is 3 feet wide.” Right in the ballpark I was looking for! He even provides a great photo of the hedge itself.
Waugh, F. A. (Frank Albert), 1869-1943. Acanthopanax (woman standing next to hedge), ca. 1925. Frank A. Waugh Papers (FS 088). Special Collections and University Archives, University of Massachusetts Amherst Libraries
I also learned through a photo on Dave’s Garden, that this species is grown as a formal hedge in Boston’s famous Public Garden. I visited the hedge on one of my trips to the Arnold Arboretum and was impressed with its small size and dense foliage. Upon measuring it, I found that it was maintained at only 3 feet (1 m) tall and 1 foot (30 cm) wide! The individual plants in the hedge were planted with a dense 1 foot (30 cm) spacing. Surely it must require frequent pruning from the garden staff to be kept so small. Apparently some members of the local Asian community had also noticed the hedge, as I came across this complaint that people were in fact harvesting and eating its leaves!
A beautiful formal hedge of fiveleaf aralia in the Boston Public Garden.
Frustrated at the lack of any English language information regarding its edibility, I decided to research the plant using its Japanese name: himeukogi or ヒメウコギ. Through this research I learned that fiveleaf aralia has been grown specifically as an edible hedge in the Japanese city of Yonezawa since feudal times. Its planting had been encouraged by the local lords and generals who saw value in its ability to secure property lines with its thorny branches while also providing important nutrition in case of famine. In fact, one of the most common ways the plant is eaten today hearkens back to its history as a famine prevention food. By boiling the leaves and adding them to rice, you can add crucial vitamins and minerals that a rice-only diet lacks, preventing the worst effects of malnutrition. Due to this long history, the people of Yonezawa continue to grow hedges of this plant (and eat them!) to this day.
A traditional fiveleaf aralia hedge in Yonezawa, Japan. Bamboo is used to provide additional support.
In addition to the historic use of fiveleaf aralia in Yonezawa, I discovered that there is actually a budding food industry being built up around the plant. Formed in 1999, the “Ukogi Town Yonezawa Hedge Association” has been growing the plant commercially and promoting its use as an edible hedge. They actually have an entire fiveleaf aralia farm that grows the plant for local farmers markets, grocery stores, and for use as a nutritious food additive. Their website is one of the best sources for fiveleaf aralia information on the web, with detailed information about the history of the plant as well as everything you need to know to grow and prepare it. Much to my surprise, they even produced a line of fiveleaf aralia flavored ice cream!
A fiveleaf aralia farm in Yonezawa, Japan.Fiveleaf aralia shoots harvested from the farm.
After reading all of this, my enthusiasm for the plant had turned into a full-on mania. A vigorous and easily-grown hedge with edible leaves, fully hardy to USDA zone 4? I had read everything I needed to know, and was ready to get some plants in the ground. Clearly the plant was safe to eat and in fact tasted pretty good. The only remaining question I had was “where can I get plants?” Only the variegated form was available in the nursery trade, and I was worried that it wouldn’t be vigorous enough to survive in full sun and make a dense hedge. (I would find out later that the variegated form doesn’t taste good anyway.) I couldn’t find the more vigorous green form of the plant for sale anywhere.
A variegated fiveleaf aralia growing at the JC Raulston Arboretum.
In my search for nurseries that sold the plants, I discovered that it was a popular shrub species for shade gardens starting around 100 years ago. It appears in countless gardening books and nursery catalogs from the time under its old name Acanthopanax sieboldianus. As it turns out, large populations of this plant still exist on old estates from that era that have been turned into parks or otherwise forgotten. If left unattended fiveleaf aralia spreads by tip-layering to form large clonal colonies similar to a blackberry. They can take over large swaths of woodland in ideal conditions.
This patch of fiveleaf aralia at the Bartlett Arboretum in Stamford, CT shows its arching habit and attractive silver-gray bark in winter.
The more prudent of you will understandably have concerns about this invasive quality. Allow me to put some of those concerns to rest. Because fiveleaf aralia spreads primarily by tip-layering, maintaining it as a trimmed hedge completely removes the main way that it gets around. The plant cannot tip-layer unless the branches are allowed to arch over and touch the ground. Fiveleaf aralia is also dioecious, and all plants in the United States appear to be female clones, so it rarely sets seed.
The inconspicuous blooms of fiveleaf aralia appear to be entirely female.The species rarely sets fruits, which are small black berries – seen here before coloring up.
Still, the species does seem to be expanding its range throughout the eastern half of the United States. While many local invasions of fiveleaf aralia can be explained as escapes from abandoned garden plantings, there are still others which are clearly caused by bird dispersal of the seeds. The good news is that it’s easy enough to remove flowers and fruit clusters from a trimmed hedge should they occur.
iNaturalist map showing occurrences of fiveleaf aralia in the eastern United States and Canada.
Eventually with the help of iNaturalist I located a large colony of fiveleaf aralia in a local park where it seems to have spread from a single ancient planting. The patch was growing in full shade on a steep slope along the side of a bridge, highlighting the incredible adaptability of the species. With well over 100 plants in the patch it would be easy for me to dig some up to transplant into my yard.
A neglected patch of fiveleaf aralia growing in full shade under a bridge.The characteristic thorns of the species occur directly underneath each leaf bud.
And so on a warm day in mid-March I ventured back to the park, dug up 28 small plants, trimmed them back, and planted them in the aforementioned location. I planted at 1 foot (30 cm) spacing as recommended by the “Ukogi Town Yonezawa Hedge Association” website and hoped for the best. It wasn’t long before the plants began to grow in earnest and by June the first inkling of a hedge was visible.
A hedge is born, March 2022.Looking good in June of 2022
As my own planting was getting established, I decided to experiment with the culinary properties of the species using leaves harvested from the patch in the local park. Raw the leaves have a green almost celery-like flavor with a bitter finish, but cooked the bitterness is significantly reduced and the flavor is that of a uniquely aromatic green vegetable. Because the bitterness is caused by water-soluble saponins, the main way to prepare the plant is by boiling the leaves. Just like spinach, the leaves cook down a lot when boiled, so it’s important to harvest a lot of them!
A big bowl of fiveleaf aralia leaves.Boiling underway
Only the young, tender leaves are edible – older leaves become too tough. This means that in the spring you can harvest all of the leaves off of the plant but throughout the rest of the year only the young growing shoots may be harvested. Thankfully the young leaves and shoots have a clearly visible color difference which makes them stand out. When harvesting the young leaves in spring you have to be careful of the thorns which occur under each leaf cluster. The young shoots are comparatively easier to harvest as you simply snap them off anywhere the thorns haven’t hardened yet. By keeping the plant as a trimmed hedge you can harvest young shoots as late in the year as September.
Young leaves in spring.Young shoots in summer.
Traditionally the leaves are eaten boiled with rice, as tempura, or as an “aemono” or Japanese chopped salad with walnuts and toasted miso all chopped together. I’ve tried all three of these traditional preparations and I enjoy them so much that I make them regularly throughout the year. The aemono in particular is delightful! This video shows its preparation as well as other traditional preparations of the plant.
Fiveleaf aralia with rice and fiveleaf aralia tempura – delicious.
In addition to the traditional Japanese uses for the leaves, I’ve also used them to make a quiche, as a topping on pizza, and as a soup ingredient, all with great results. Because the leaves are fairly mild, they’re suitable for a wide range of uses. After boiling the leaves, the water can be pressed out and the leaves may be frozen for future use.
Vegan quiche made with fiveleaf aralia from the freezer.
Regarding the nutrition of the plant, fiveleaf aralia could rightly be called a superfood! The word “adaptogen”, which has been so widely used to describe highly nutritious wild food plants, was originally coined to describe Eleutherococcus senticosus, a close relative of Eleutherococcus sieboldianus. While Eleutherococcus senticosus is much too bitter to be used as a food plant, Eleutherococcus sieboldianus can provide similar benefits in a more palatable package. Research on the nutrition of the species is still ongoing, but all indications point to it being a good source of vitamins A, C, E, calcium, magnesium, iron, zinc and folate in addition to the medicinal and antioxidant qualities of the saponins and polyphenols found in its leaves.
The author with his young hedge in June of 2023 – sheet mulching in progress at left. Photo by Mike Amato.
The hedge I planted grew quickly and reached full size in around 2½ years after planting. I keep it trimmed to 4 feet (1.2 m) in height and 2 feet (0.6 m) in width. As Frank A. Waugh said in “Experiments with Hedges”, the plant does require conscientious pruning due to its fast rate of growth. This is less of a problem when you’re eating the leaves, because each pruning session is also a harvest session! This is that magical synergy I was looking for!
The hedge reaching full-size in June of 2024.
Looking back, I can only say that “the incredible edible hedge” has been a tremendous success. The hedge looks great and is protecting my young food forest admirably. The dishes I’ve made with fiveleaf aralia have become some of my favorites, and I look forward to making them each spring. The fiveleaf aralia harvest is mainly limited by my patience in picking the leaves and shoots, so I’m currently exploring tools to help automate the process such as devices for stripping leaves from branches and a hedge trimmer with a basket for catching trimmings. I’m hoping that others will learn about the many benefits of this plant, and many more “incredible edible hedges” will be planted soon!
