Hardy Edible Plants

Tag: Asian plants

  • Koshiabura – The Elusive “Queen of Sansai”

    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!

  • The Uncommon Spicebush

    The very first plant I learned to forage was the common spicebush, Lindera benzoin. My foraging teacher “Wildman” Steve Brill pointed out the bush and explained to us that it could be easily identified by the lenticels on its bark and the fragrance it emits when a branch is broken. He recommended collecting the berries in the fall to use as a potent spice. Since that time I’ve been collecting spicebush berries every fall. My favorite way to use them is to blend one or two berries into a smoothie for a spicy kick. I think the flavor is more akin to nutmeg, cardamom, or allspice than anything else.

    Spicebush berries on the bush.

    One common mistake people make with spicebush berries is attempting to store them dried. The spicebush berry is high in fat, so it should be stored frozen to prevent the fats from turning rancid. Its high fat content is one reason why it’s a favorite food of migratory songbirds, who need that energy to fuel their migration. I’ve always admired the resilience of the common spicebush, as it’s one of the few native plants in the northeast that can compete with invasive plants in the forest understory. I grow a male and female here in my garden.

    The spring flowers of common spicebush.

    Eventually I learned that there are some uncommon varieties of the common spicebush. My favorite local nursery Broken Arrow Nursery, which specializes in rare and unusual plants, sells Lindera benzoin ‘Rubra’, a male variety with red flowerbuds. This variety was discovered on the side of the road by Dr. Brian Maynard of the University of Rhode Island. I got to meet him and take cuttings from one of his plants, but I failed to get them rooted or grafted. As it turns out, the common spicebush is very difficult to propagate.

    The red flower buds of Lindera benzoin ‘Rubra’.
    Photo provided by Dr. Brian Maynard.
    Lindera benzoin ‘Rubra’ in bloom.
    Photo provided by Dr. Brian Maynard.

    Another almost-mythical form of the common spicebush is Lindera benzoin ‘Xanthocarpa’, a female form with yellow rather than red fruits. This mutation occurs randomly in wild populations, and is exceptionally difficult to find because it can only be seen when the bushes are fruiting. In the winter of 2021 I searched through all sightings of fruiting Lindera benzoin on iNaturalist and managed to find a few examples of this form. You could say that my searching “bore fruit”. Unfortunately the seeds I received from a kind iNaturalist member failed to germinate.

    Photo from iNaturalist user laddercorn
    Photo from iNaturalist user zebraweeds

    I’ve always thought it would be funny to grow ‘Rubra’ and ‘Xanthocarpa’ side by side. You’d have a male spicebush with red flowers that should be yellow next to a female spicebush with yellow fruits that should be red. Sadly I’ve been unable to make it happen, though I continue to try!

    Global distribution of the genus Lindera based on iNaturalist observations.

    As the years have gone on, I’ve learned to appreciate the other non-native members of the genus Lindera as well. There are far more spicebush species in Asia than there are in North America after all. Two of my favorites are Lindera angustifolia and Lindera obtusiloba, the narrow-leaf and blunt-lobed spicebushes respectively. I always seek these plants out on my trips to botanical gardens and arboreta.

    The narrow leaves of Lindera angustifolia.
    The lobed leaves of Lindera obtusiloba.

    Lindera angustifolia or narrow-leaf spicebush is an East Asian species with excellent fall color and an interesting quirk. Rather than dropping its leaves in the fall, it holds onto them firmly all winter long. I’ve planted a hedge of this species along the back of my property to form a pseudo-evergreen barrier between my yard and my neighbor’s. The wind blowing through the leaves in winter makes a pleasing sound similar to a bamboo grove, without the invasive qualities.

    The vibrant fall color of Lindera angustifolia.
    The persistent leaves of Lindera angustifolia.

    Lindera obtusiloba or blunt-lobed spicebush is a larger tree-like species that has three-lobed leaves similar to our native Sassafras. The blunt-lobed spicebush’s most striking feature is its reliable fall color. It turns a vibrant yellow-orange every fall without fail, even in woodland settings or when conditions for fall color are poor. The Plants for a Future database says “Young leaves are fried and used as a Buddhist ceremonial dish”, but I’ve found no evidence of this. I guess I’ll have to fry some up sometime and have a taste.

    Lindera obtusiloba in bloom at the New York Botanical Garden..
    Lindera obtusiloba in fall at the Arnold Arboretum.

    Both of these Asian spicebushes have yellow flowers in the spring, similar to the common spicebush. The blunt-lobed spicebush has larger flowers in proportion to its larger overall size, while the flowers of the narrow-leaf spicebush are hidden behind its persistent leaves. The Asian spicebushes also produce a small fruit, which is decidedly less edible than the native species. On the one occasion that I ventured to taste it I was immediately punished by its terrible bitterness! As far as spicebush fruits are concerned, you could say that the fruits of the common spicebush are uncommonly delicious.