Japanese arrow bamboo

Profile

Family

Poaceae

Habit

Shrub

Height

4.8 m

Spread

6 m

Growth

very fast

Lifespan

30 years

Hardiness

zone 5–9

Shade tolerance

full shade

Soil

Sand, Silt, Loam, Clay

Soil moisture

dry – very wet

pH

5.5 – 7.5

Synonyms

Pfeilbambus

Uses

Edible: Young shoots - cooked. Harvested in late spring, about 8 - 10 cm above the ground, cutting the stems 5 cm or more below the ground. They have a rather bitter taste. Seeds - used as a cereal. Small amounts of seeds are produced in many years, but it is rarely viable.

Medicinal: The plant's bark possesses astringent, soothing, and tonic properties. A decoction of the bark was traditionally used to treat digestive disorders, stomach upsets, diarrhea, coughs, colds, and respiratory issues. A decoction of the bark was applied for wound healing, and the dried, powdered bark was used as a dusting powder for wounds. The steam from boiling the bark was used to treat snow blindness. A decoction of the wood waste was employed for intestinal complaints. Compresses with the leaves were applied to abscesses, cuts, wounds, bruises, and black eyes. The ripe fruit has a laxative effect. All plants of this genus contain amygdalin and prunasin, which can break down into hydrocyanic acid in water. In small amounts, hydrocyanic acid can stimulate respiration, improve digestion, and provide a sense of well-being.

Other uses: Plants along the riverbank can help protect the banks from erosion. The stems are thin-walled but make good plant supports. Smaller stems can be woven together and used as privacy screens or for decoration on walls and ceilings. The plant is tolerant of maritime exposure and can be grown in very exposed areas as a visual or windbreak hedge. The stems act as an effective wind filter, reducing wind speed without creating turbulence. While the leaves may look tattered at the end of winter, the plants soon produce new leaves.

Growing

One of the easiest bamboo species to grow prefers an open, good quality clay soil and a sheltered position from cold, drying winds, although it also tolerates maritime exposure. It thrives in peaty soils and soils consisting half of earth and half of stone. The bamboo requires ample moisture and plenty of organic matter in the soil, tolerating nearly saturated soil conditions but not drought. This highly decorative plant is considered the hardiest bamboo, enduring temperatures of about -15°C. In warmer regions, the bamboo can reach a height of 6 meters or more. The root system is runner-forming and highly invasive, but can be easily controlled by removing unwanted new shoots early. New shoots appear from April. This species is particularly resistant to root rot. Plants often bloom lightly over several years without dying out, although they rarely produce viable seeds. Occasionally, the plants can produce an abundance of flowers, weakening them significantly but usually not killing them. It may take several years for them to recover. Feeding the plants with artificial NPK fertilizers during this time is more likely to cause plant death. Many plants bloomed heavily in the late 1980s and are only slowly recovering.

Propagation

Sow seeds directly in a greenhouse at around 20°C after they have ripened, or sow stored seeds promptly. Keep the soil moist to facilitate germination, which typically occurs quickly with good quality seeds, although it may take 3-6 months. Transplant seedlings when they are large enough to handle, and grow them in a slightly shaded area in the greenhouse until they are ready for planting out, which can take several years. Plants only bloom at multi-year intervals, making seeds rarely available. Divide in late spring when new growth begins by using individual shoots from the current year. Pot them in light shade in a greenhouse, ensuring the foliage stays hydrated - spraying 2-3 times a day in the first few weeks after division can be very beneficial. Plant them out in the summer once they are growing vigorously. Layer shoots in May by separating individual shoots and laying them horizontally in 15 cm deep trenches. New shoots should emerge from each joint.

Notable

Special features: sea + wind tolerant. The stalks are an excellent wind filter, slowing down its speed without creating turbulence. Stalks are used as arrows. Two-year-old stalks are dried over a fire and smoothed by grinding.

Origin & habitat

E. Asia - Japan. Commonly naturalized in Japan.

Along rivers and streams, the plant thrives in deep, moist floodplain soils, preferring areas with high humidity and well-drained soil.

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