Cleistocactus is a cactus genus native to South America and found especially widely distributed in Argentina, Peru, Uruguay, and Bolivia. In addition to growing in the wild, these cacti are also cultivated by gardeners all over the world. They can be grown as houseplants and also in cactus and succulent gardens in warm climates. Gardeners interested in growing a Cleistocactus species can find specimens at garden supply stores and nurseries, particularly those specializing in cacti and succulents.
These cacti grow in erect columns, typically producing a number of slender columns at the base of the plant. Many species are covered densely in hair as well as spines. The hair and spines can vary in color from silver to gold and some species can grow as high as 10 feet (three meters) tall. Cleistocactus species are fast growing and visually striking, making them a very popular choice for landscaping in some regions of the world.
To protect the flowers from heat and dust, the plant only allows them to open partway during blooming. Cleistocactus means “closed cactus,” describing the partially closed nature of the flowers. Depending on the species, the flowers can be orange, yellow, red, or golden in color, and they will appear during the spring and summer. Gardeners cultivating these cacti can encourage extended flowering by adding a potassium-rich fertilizer to the soil in the spring.
Like other cacti, Cleistocactus has relatively low water requirements. It should be grown in rich, well drained soil and thrives in United States Department of Agriculture zones nine and 10. Other cacti and succulents make good companion plantings. Due to their height, plants in this genus make good specimen plants in the garden, and they can also be used as backdrops in large beds. Mulching a garden with a gravel mulch will help keep weeds out of cactus and succulent beds, in addition to helping the soil retain moisture.
Gardeners in hot regions with water restrictions who want to attract bees, butterflies, and birds may want to consider growing Cleistocactus, along with other flowering cactus species. The bright flowers are very attractive to animal visitors, and during the flowering season, a steady flow of bird and butterfly species should visit the garden. These plants are also very suitable for low water gardening and can be an excellent choice for gardeners working with concerns about water usage in mind. These plants can be propagated from cuttings, as well as seeds.