Dendrobium orchids are native to Southeast Asia where the flowers are epiphytic; they grow on trees, not in the soil. Several species have white inflorescence and the long, sweeping flowers make them an attractive and popular decorative indoor flower.
Dendrobium orchids grow easily in a soilless mixture, such as on cork or tree bark, or in a specially formulated orchid potting mix. Because they are epiphytes and receive both nutrients and water from the air with their large roots, dendrobium orchids should never be planted in the soil.
Dendrobium orchids require humidity to remain between 40 and 60 percent, according to Clemson University. In most homes, orchids should be planted over a small tray with water to maintain humidity levels. Ensure there is adequate air circulation at the planting location to prevent bacterial and fungal problems for the orchid.
White dendrobium orchids have long stems — over 12 inches in length — that produce abundant flowers. The white flowers may remain on the plant for three to four weeks and can bloom multiple times in a year.