The bamboo orchid or Arundina graminifolia is a species of orchid and the sole of the genus Arundina. This tropical Asiatic genus extends from India, Nepal, Thailand, Malaysia, Singapore, and South China to Indonesia and across the Pacific Islands. It has been introduced in Puerto Rico, Costa Rica, and Panama. The bamboo orchid is a terrestrial multi-perennial orchid with reedy stems, forming into large clumps growing to a height between 3 and 10 feet.
This orchid blooms in summer and autumn, showing rather open clusters of up to 10 showy terminal flowers. They bloom in succession on the terminal racemes with the flowers being a rosy lilac and white disk with a purple lip. The bracts are wide triangular and surround the main stalk of the flower cluster. The occasional fertilized seed pods contain minute powdery seeds and small plants often develop near the cane ends after flowering and likely aid in propagation if allowed to reach the soil.
Bamboo orchids grow best in light, rich, organic soil. If you grow a bamboo orchid in a pot, use a potting mix of equal parts of fine fir bark, sphagnum moss and sand. Before planting a bamboo orchid outside, work partially decomposed pine bark, well-rotted compost, and peat into the soil until the organic matter makes up 60 to 70 percent of the planting mix. They grow best in areas with lowest temperatures in the 40s Fahrenheit, although they can tolerate light freezes.
Increase your bamboo orchids by dividing the roots of the plant into several sections, with three or four growing stems per section. Cut the stems back by half and plant each section in a pot of planting mix or in the ground in an area that has been amended with organic matter. Another way to increase your bamboo orchids is to remove the keikis from the stems. Plant keikis with no roots in damp sand until the roots grow at least two inches long. Then plant the keikis with roots in pots of planting mix until the roots are well established, and new growth appears from the stems. When this happens, you can then plant them in a larger pot of planting mix or in the ground in soil amended with organic matter.
Bamboo orchids are so named because the tall stems look like bamboo and the flowers resemble the blooms of Cattleya orchids. The flowers are fragrant and attract butterflies and bees.
You will probably not find this orchid in the shops – it is a specialist orchid that is prized for its profuse flowering and beautiful honey scent.