Oncidium ensatum is usually epiphytic but sometimes terrestrial, up to 100 cm (39 in) tall (not including the inflorescence). The leaves are narrowly linear to lanceolate, each up to 10 cm (3.9 in) long. The inflorescence is either arching or hanging, up to 250 cm (98 in) long. The flowers are yellow with brown spots.
Plants should be watered thoroughly with lukewarm to room temperature water every two to ten days, when the planting media is half dry
Oncidiums are light-loving orchids, with some able to handle direct, full sun. The vast majority will do well placed near an east, west, or south facing window with a sheer curtain to diffuse the light and provide the dappled shade these tree-growing orchids are used to.