Cleistocactus is a genus of columnar cacti from Peru, Uruguay, Bolivia and Argentina. Cleistocactus is a popular cactus genus containing between 50 and 100 species depending on the author. In the recent years a number of genus have been regrouped in Cleistocactus, making this genus quite large. Species from these genus have been included: Akersia, Bolivicereus, Borzicactella, Borzicactus, Hildewintera, Seticereus, Seticleistocactus, Winteria, Winterocereus, Yungasocereus. The name Cleistocactus comes from the Greek for "closed cactus" referring to the appearance of the flowers. Suitable for the home or a greenhouse. They are easy and usually fast growing. Cleistocactus are slender stemmed sometimes hairy shrubs but some species are thicker and some do branch up from the base. Straight or slightly bent flowers are long and thin not opening widely, only the style and stamens usually protruding, in july through september. Flowers have many color combinations but red is the most dominent color. Hardiness zones 9-11, (-5øC/25øF, 4øC/40øF). They need medium humidity. Regular water in summer, keep rather dry in winter. They are mostly robust plants which are easily grown in well-drained soil in a sunny spot.