In the October garden, the leaves on fo-ti vines that have climbed up their stakes are starting to turn yellow. In the Northern Hemisphere, this is when you dig fo-ti, also known as he shou wu. Frost kills the vines, but the tuberous roots survive the winter underground and send up new shoots the next spring. Fo-ti is fairly hard to grow, mostly because it needs deep soil that drains well, and that kind of spot is hard to find.
Planting: Check the Name, Then Plant in Deep Soil
Fo-ti (Polygonum multiflorum), called hasuo in Korean, is a climbing vine in the knotweed family. It grows by twining around whatever it can reach, and the tips of its roots swell into tubers. Before you buy any tubers, make sure you know what you're getting. Koreans have traditionally called the red type jeok-hasuo ("red hasuo") and the white type baek-hasuo ("white hasuo"). But the plant long sold as white hasuo, Cynanchum wilfordii, is in the milkweed family. It isn't even in the same family as true fo-ti, which belongs to the knotweed family. In 2015, Korea had a major scandal when a look-alike plant, Cynanchum auriculatum, was found mixed into products sold as white hasuo. When you buy plants or tubers, check the scientific name on the label as well as the common name.
In the Northern Hemisphere, plant in March or April. Fo-ti is grown from tubers. Choose a spot with deep soil that drains well. If water collects around the tubers, they will rot. In a garden bed, mound the rows up high so water runs off. In a container, use a deep pot and check that it has plenty of drainage holes. Put in stakes for the vines to climb on the same day you plant.
Care: Train the Vines Upward and Keep Water from Pooling
Fo-ti grows at temperatures from 5 to 32°C and does best between 15 and 25°C. It likes the warmer parts of the temperate zone, where summers are hot and rain falls steadily through the year. The plant is native to China, grows wild in Taiwan, and is widely grown in Korea. Check your area's midsummer highs and midwinter lows against this range to decide whether to plant it in the ground or keep it in a pot.
Once the vines come up, guide them onto stakes or netting. Vines left to tangle on the ground are a chore to clear away in the fall. During stretches of heavy rain, check often for water standing in the furrows. If you find any, dig a channel the same day to let it drain.
In winter, frost withers the vines, but the tubers underground survive. If you leave them in the ground, new vines will come up in the same spot the next spring.
Harvest: When the Vines Die Back, Dig Wide
In the Northern Hemisphere, harvest in October or November. When the leaves turn yellow and the vines start to dry out, pull the vines off their stakes and dig a wide circle around the plant. The tubers form at the ends of the roots, so if you dig only right under the plant, you can easily miss them. The Dongui Bogam, a medical text compiled in Korea's Joseon dynasty in the early 17th century, says the root grows as large as a fist. Prepare the tubers you dig up as follows.
- Wash off the soil and slice them thin.
- Spread the slices in the sun and let them dry all the way through. Whole tubers don't dry in the middle and tend to mold.
- When the slices are completely dry, store them in an airtight container in a cool place. Put anything you want to keep for a long time in the freezer.
Eating: Reduce the Bitterness and Make Tea
Dried fo-ti slices can be simmered into tea, ground into powder, or steeped in liquor to make an infused spirit. Several studies have isolated stilbene glycosides from the tuber, along with anthraquinones such as emodin and chrysophanol. The tuber feels heavy and solid because it is full of starch, which the plant stores there. If you simmer the root raw, tannins leach out and the tea tastes strongly astringent.
For that reason, sliced fo-ti has traditionally been soaked in the liquid left from cooking black beans, then steamed and dried in the sun, and the whole process repeated several times. Fo-ti treated this way is called jehasuo, or prepared fo-ti, to set it apart from the raw root. The process is known as beopje, the traditional method of steaming and drying medicinal herbs. Processing darkens the root and makes it less astringent. Some analyses suggest that the steaming and drying also change its chemical makeup. Because the process takes so much work, most people buy fo-ti that has already been processed.
When you make the tea, try adding jujubes (Korean red dates) or licorice root. They add sweetness that covers some of the astringency. Once the water comes to a boil, turn the heat down and let it simmer gently. Make only as much as you'll drink in one day, and finish it that day.
The Dongui Bogam lists hasuo (何首烏) in its section on herbs, called Chobu (草部). It describes the root as neutral and warming in nature, bitter, astringent, and sweet in taste, and not toxic. The text also tells where the name came from. The plant was originally called yagyodeung (夜交藤, "night-entwining vine"), and it was renamed hasuo after a man named Ha Su-o (He Shouwu in Chinese) ate it. These are descriptions from an old medical text, and modern medicine does not necessarily agree with them. If you plan to take fo-ti regularly as a medicinal herb, talk with a doctor or pharmacist first.
Today, choose one plant with faded leaves and dig wide around it. Then slice the tubers thin and spread them out in the sun.
Source: Dongui Bogam, Chobu (草部), "Hasuo" (何首烏)
