Plant a single castor aralia at the edge of your garden, and sooner or later someone will stop to stare at the thick, broad spines crowded along its trunk. Their questions are usually the same. Is this the tree that goes into baeksuk, Korea's simmered whole-chicken soup? Is it the same thing as haedongpi? Can you steep the bark and drink it every day? Many people know you can blanch and eat the spring shoots, which Koreans call gaedureup (a cousin of the prized aralia shoots known as dureup). The bark is a different matter. What people say about it, what the old texts record, and what chemical analysis shows don't agree.
Castor aralia (Kalopanax septemlobus) is a large deciduous tree in the aralia family, native to Korea, China, Japan, and Russia. Its palm-shaped leaves are divided into 5 to 9 lobes. Mature trees grow taller than 10 meters, so a corner of the yard or the edge of a field suits them better than a small vegetable plot. In the Northern Hemisphere, transplant saplings in early spring, in March or April. It takes several years before a tree is big enough to harvest shoots.
Where does the name haedongpi come from?
In Korea, castor aralia bark has long been used under the name haedongpi (海桐皮), a name that comes from old medical texts. The Donguibogam, the classic 17th-century Korean medical encyclopedia, has a haedongpi entry in its section on trees. That entry describes the bark's nature as neutral in one place and warm in another, and its taste as bitter and nontoxic. It says the bark resembles the white bark of the Chinese catalpa and can be stripped in any month. It also notes that in Korea at the time, the tree grew only on Jeju Island.
Today castor aralia grows in mountains all over Korea, and farmers cultivate it as well. That doesn't fit the old claim that it grew only on Jeju, so it's fair to ask whether the haedongpi of the old texts was really this tree. Opinions differ. Castor aralia bark has certainly been called haedongpi, but there isn't enough evidence to say the two are the same thing. The Donguibogam is also a historical record, not the judgment of modern medicine. When you hear the word haedongpi, don't take the old texts' descriptions as proof of what castor aralia bark can do.
Compounds isolated from the bark
Chemical analysis looks at a narrower question than the old texts do, but it gives more concrete answers. Researchers have reported isolating a compound called kalopanaxsaponin from castor aralia bark. It is a glycoside in the triterpenoid saponin family and contributes to the bark's bitterness and its tendency to foam. The tree also contains polyphenols, which account for astringency and make cut surfaces turn brown, and dietary fiber in the form of the polysaccharides that build cell walls.
The same research also measured how much saponin the bark holds. Levels varied widely depending on which part of the tree was sampled and when it was harvested. That means the amount in any single piece of bark will likely depend on where it came from and when it was gathered. Keep in mind that this kind of analysis only shows what the bark is made of. Modern research has not yet confirmed what it does in the body when people eat it.
One or two pieces in the baeksuk pot
The most common use for castor aralia bark is in a pot of baeksuk. Add a piece and let it simmer for a long time, and the broth picks up a faint aroma and a slight, pleasant bitterness. Korean cooks have done this for generations. The right amount is one or two pieces, just enough to flavor the broth. If you add a lot of bark hoping for a richer broth, the flavor turns heavy and murky instead.
If you're making it at home, keep these points in mind:
- Start with one piece of bark, and never use more than two.
- Even if the aroma seems faint, don't add more.
- When the soup is done, lift out the bark and serve only the broth.
Is bark tea safe to drink every day?
Steeping castor aralia bark in water and drinking it is a long-standing folk practice. But as noted above, no one has confirmed how the bark acts in the body, and its saponin content reportedly varies widely by part and harvest time. So it's hard to know what's in a cup brewed at home, or how much. We don't recommend going beyond the one or two pieces in a pot of baeksuk, and we don't recommend drinking a strong brew every day as if it were medicine.
If you take medication or are pregnant, be especially careful to avoid bark tea. If you've already been drinking it, tell your doctor or pharmacist.
Don't eat the spring shoots raw. Blanch them in boiling water with a pinch of salt for 30 seconds to 1 minute, then rinse them in cold water before using. To learn more about preparing the shoots and when to plant, see the Homiclub castor aralia crop guide.
If you have dried castor aralia bark at home, try putting just one piece in your next pot of baeksuk.
Sources: Donguibogam, section on trees, haedongpi entry; published analyses of saponins in castor aralia bark.
