The Wild Taste of Spring: Japan’s Bitter Mountain Vegetables

In Japan, edible wild plants that grow naturally in the forests and fields are called sansai, or mountain vegetables. While certain sansai can be enjoyed year-round, those harvested in spring are particularly prized for their exceptional flavor.

The custom of eating sansai in Japan dates back about 10,000 years ago to the Jomon period. As agriculture developed, people began cultivating crops instead of relying solely on hunting, fishing, and foraging. However, in early spring, when the weather was still cold, farm-grown vegetables were scarce. To supplement their diet, people turned to the fresh, tender young shoots and leaves sprouting in the wild.

Even as agricultural techniques advanced and a variety of vegetables became available year-round—including in the depths of winter—the tradition of eating sansai persisted. Today, sansai remains a beloved ingredient in springtime cuisine, adding color and flavor to dishes such as tempura and simmered dishes.

Many sansai contain bitter compounds that help protect them from insects and animals. This bitterness is considered one of the five basic tastes—alongside sweetness, sourness, saltiness, and umami—and is an essential component of food flavor. The distinctive bitterness, the refreshing aroma unique to wild plants, and the delicate, pale green appearance of sansai have become symbols of Japanese spring. They serve as a natural gift from the wild, heralding the end of winter and the arrival of a new season bathed in sunlight.

Sansai represent Japan’s deep appreciation for seasonality in food culture. In this article, we explore the fascinating world of spring sansai and their significance in Japanese cuisine.

Japan is home to approximately 200 to 300 types of edible sansai. While traditionally consumed in rural and mountainous regions, they are now enjoyed in urban areas as well.

However, even the most commonly cultivated varieties amount to only 9,000 tons annually, representing just 0.07% of total vegetable production in Japan—making them quite rare. For those unfamiliar with Japanese cuisine, sansai might be an entirely new discovery.

Here are some of the most well-known spring sansai in Japan:

Warabi grows in well-drained, sunny areas across Japan. Its tightly coiled young shoots, which resemble clenched fists, have a slightly slimy texture when cooked and are commonly used in stews, miso soup, and salads. Starch extracted from its roots, known as warabiko, is used to make warabi mochi, a traditional Japanese sweet.

Zenmai thrives in mountains, meadows, and wetlands and grows up to 50 cm–1 meter (19.7–39.4 in) in height. The young, curled shoots harvested in early spring are traditionally boiled and dried for preservation. Once rehydrated, they have a firm, crunchy texture and are used in stir-fries, stews, and miso soup.

Tara-no-me are the young buds of the Japanese angelica tree, which grows in sunny areas along roadsides and grasslands across Japan. These shoots have a tender texture and rich flavor and are often enjoyed as tempura, in salads, or stir-fried. Today, most tara-no-me sold in markets are cultivated rather than wild.

Fuki is a plant that grows in moist riverbanks and mountain valleys from Honshu to Kyushu. Its flower buds, known as fuki-no-tou, appear in early spring and are commonly deep-fried as tempura or simmered into tsukudani (soy-simmered dish). The stalks and leaves of fuki are also eaten in various dishes.

A large plant that grows up to 1–2 meters (39.4–78.7 in), udo is found in mountainous areas across Japan. The young shoots and tender leaves are used in stir-fries, salads, and tempura. Wild udo has an intensely aromatic, earthy flavor that is especially prized. Due to its popularity, cultivated varieties are also available.

Yomogi grows in sunny meadows and riverbanks throughout Japan. Its tender leaves and tips are used in tempura, adding a crisp texture and refreshing aroma. It is also ground into a paste and mixed into rice cakes to make kusa mochi, a popular traditional sweet.

As mentioned earlier, sansai has been a part of the Japanese diet for over 10,000 years, dating back to the Jomon period. Archaeological sites from this era have revealed evidence of at least 40 different kinds of sansai consumed by ancient Japanese people.

By the Nara period (629–759 AD), as many as 20 different types of sansai had been mentioned in Japan’s oldest poetry anthology, the Manyoshu. The following poem captures the deep connection between spring sansai and nature.

"Iwa bashiru / Tarumi no ue no / Sa-warabi no
Moeizuru haru ni / Nari ni keru kamo"

Translation:
"The spring has come—
Bracken fern shoots are sprouting
By the rushing waterfall above the valley."

This poem reflects the joy of witnessing the first sprouts of sansai, signaling the arrival of spring—a sentiment deeply ingrained in Japanese culture for over 1,300 years.

Sansai often contains a characteristic bitterness, known as egumi. This tannic, slightly astringent flavor is due to plant alkaloids, which are thought to aid in detoxifying the body.

During winter, cold temperatures slow circulation, leading to the accumulation of waste products in the body. The natural compounds in sansai help eliminate these toxins, a fact that Japanese people may have understood intuitively. This idea is encapsulated in the saying:

"Serve bitterness on spring plates."

This proverb suggests that eating bitter foods—especially sansai—helps refresh and rejuvenate the body in spring.

Even non-sansai spring vegetables such as nanohana (canola flowers) and takenoko(bamboo shoots) also share a characteristic bitterness, offering similar health benefits.

Even though sansai is rich in seasonal significance and health benefits, its bitter taste can be a challenge for some. If it were too unpleasant, people wouldn't have continued eating it for over 10,000 years. Over time, Japanese people developed various cooking techniques to make sansai more palatable while still preserving its unique characteristics.

Here are three key techniques to enhance the enjoyment of bitter sansai:

One of the most common methods is soaking sansai in water or vinegar water or boiling it to reduce bitterness. This method is also used for canola flowers and bamboo shoots, although in the case of bamboo shoots, the bitterness is strong, so they must be boiled for a long time with rice bran or chili peppers to fully remove the harsh taste.

Bitterness can be softened by seasoning sansai with miso, sugar, or salt. Additionally, deep-frying, as seen in sansai tempura, balances the bitterness with the richness of oil, making it more enjoyable.

Rather than making sansai the main ingredient, it can be mixed into other dishes or used as a garnish. By incorporating sansai as a flavor enhancer, its bitterness can complement and enrich the overall dish.

Interestingly, these cooking methods do not completely eliminate the bitterness but rather moderate it, allowing just the right amount to remain. This subtle balance is key to appreciating the true depth of sansai’s flavor.

Expanding on this idea, recent studies suggest that koku (depth of flavor)—a key indicator of deliciousness in food—is enhanced when umami compounds, fats, and bitterness coexist.

A perfect example of this is fuki-miso, a traditional Japanese dish made by chopping and stir-frying butterbur buds in oil and seasoning it with miso, mirin, and sugar. This dish beautifully integrates the rich umami of miso, the depth of oil, and the distinctive bitterness of butterbur buds, creating an exceptionally well-balanced and flavorful experience.

For an even more profound taste, pairing fuki-miso with fatty grilled fish or meat further elevates the complexity and richness of the dish, demonstrating how bitterness, when used skillfully, enhances the overall depth of flavor.

If you find yourself in a Japanese restaurant in spring and encounter an unfamiliar vegetable, it might just be sansai.

These nutritious wild greens, long valued for their health benefits, are a delightful way to experience Japan’s seasonal traditions.

Rather than hesitating at their bitterness, why not embrace the taste of Japanese spring?

Important Notice:
If you are foraging for wild sansai, please remember that harvesting is not permitted on private property, national parks, or nature reserves where plant and animal collection is restricted.

Additionally, some wild plants can be toxic. Unless you have expert knowledge, do not attempt to determine whether a plant is safe to eat on your own. Always consult a professional before consuming foraged plants.