Once-in-120-Years Bloom of Henon Bamboo – The Mystery of Flowering and Its Impact on Bamboo Forests

In the early 2020s, bamboo groves across Japan began turning brown and withering. The cause: Henon bamboo (Phyllostachys nigra var. henonis), one of Japan’s three most important bamboos, flowered for the first time in about 120 years.

At Sentei-ya Sora, we manage several Henon bamboo forests in Suzuka City, Mie Prefecture. While flowering has not yet been observed in these groves, we are closely monitoring them to understand how they may change in the coming years.

What is Henon Bamboo?

• Scientific name: Phyllostachys nigra var. henonis

• Origin: China (introduced to Japan during the Nara period, 8th century)

• Height: 10–15 m (up to 20 m in favorable conditions)

• Diameter: Around 10 cm

• Characteristics: Pale green culms covered with a whitish powder; highly cold-

  tolerant

  
  

Henon bamboo has long supported Japanese life and culture:

• Crafts: ideal for tea whisks (chasen), lanterns, fans, brooms, blinds, and writing brushes

• Food: its tender spring shoots are prized seasonal delicacies

  
  

The Enigma of the 120-Year Bloom

Bamboo flowers are rarely seen in a human lifetime. In the case of Henon bamboo, mass flowering occurs roughly once every 120 years.

• Appearance: The flowers resemble small rice-like spikelets dangling from branch tips—so subtle that flowering is often overlooked.

• Aftermath: Once flowering begins, the culms (stems) weaken, turn brown, and eventually die within months to a few years.

  
  

A research team at Hiroshima University reported that during the recent bloom, 83% of 334 monitored culms flowered and died shortly after (2020–2022). Larger culms were more likely to flower, suggesting a synchronized “life reset” across clonal stands.

What Happens After Flowering?

Ecological & Cultural Impacts

• Mass die-off and collapse: Dead culms become hollow and fall easily, creating hazards near homes and roads.

  
  

• Landscape changes: Lush green slopes suddenly shift to brown, alarming local residents and altering scenic areas.

  
  

• Economic effects: Loss of bamboo shoots and bamboo materials disrupts traditional crafts (e.g., tea whisks, bamboo baskets).

  
  

Why No Seeds?

Henon bamboo rarely produces viable seeds. Because entire groves are clonal, pollination is difficult. Instead of relying on seeds, Henon bamboo regenerates from underground rhizomes.

Underground Survival

Even after aboveground die-off, rhizomes often remain alive. After several years of dormancy, they may send up thin new shoots. Regeneration pace varies, but forgotten bamboo groves can revive decades later.

Henon Bamboo as Food and Medicine

Culinary Value

• Season: April–May

• Taste: Mild, low bitterness, tender fibers

• Dishes: simmered with wakame (wakatake-ni), bamboo rice, tempura, miso soup

• Note: When freshly harvested, no pre-boiling with rice bran is needed

So rare that Henon shoots are sometimes called the “phantom bamboo shoot.”

Medicinal Uses (from classical Chinese medicine)

Bamboo has long been valued not only as a material but also for its medicinal properties, recorded in the ancient text Shennong Bencao Jing.

Parts used include:

• Leaves (Zhú yè): cooling, detoxifying, reduces fever and inflammation

• Inner bark (Zhú rú): relieves coughs, calms restlessness in children

• Resin (Zhú huáng): stabilizes the mind, used for insomnia and epilepsy

• Shoots (Zhú sǔn): high in fiber, aid digestion and detoxification

Cultural Symbolism – “The Gentleman’s Bamboo”

In Chinese philosophy, bamboo is one of the “Four Gentlemen” (梅梅, orchid, bamboo, chrysanthemum), symbolizing virtues of the ideal person:

• Hollowness = humility

• Straight growth = integrity

• Flexibility with strength = resilience and discipline

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The phrase “君子の用 (Junzi’s Use)” highlights bamboo not just as a practical material but as an embodiment of noble character and refined culture.

Conclusion – The Bamboo’s Century-Long Drama

The flowering and withering of Henon bamboo is a rare natural spectacle—a dramatic act in a play staged once every century.

Though it may bring short-term loss and altered landscapes, underground rhizomes quietly prepare for renewal. At Sentei-ya Sora, we aim to accompany this rhythm of life, managing fallen bamboo safely while exploring ways to upcycle bamboo resources.

Perhaps 120 years from now, another generation will witness this cycle anew, feeling the deep connection between bamboo, people, and the passage of time.