Rhododendron columbianum is a shrub up to 2 m (6 ft 7 in) tall, spreading by means of underground rhizomes. The evergreen leaves are ovate to lanceolate, fragrant when crushed. Flowers are white to cream, borne in groups of 10 to 35. It grows in wet places from sea level up to 3,500 m (11,000 ft). It was formerly known as Ledum columbianum. It has been used medicinally as a tea astringent, diaphoretic, diuretic and laxative properties. The plant can, however, be toxic if the tea is allowed to steep too long. The fragrance of the leaves has also been shown useful in repelling insects and rodents.