Cleistocactus are a very good compromise if you are looking for a bit of variety and want some taller-growing plants to complement the more low-growing varieties. Many tall-growing plants are available, but few are as decorative as these. As with most larger varieties, the size which is attained depends largely upon how much freedom they are given. Plants which are moved on regularly, or allowed root-space in a proper bed will rise to a metre or more and branch from the base to make attractive columnar groups. The only down-side is that some varieties have a tendency to droop and sprawl as they age, which can be very space consuming. Some plants have short, stiff spines which barely cover the stem of the plant, while others have such dense spination that the stem is invisible. Others are extravagantly spiny and have the sharpest and most pentrating armament in my collection. New shoots which arise from the base are usually furnished with soft, silver-grey spines and the stiffer, more colourful central spines do not tend to arise until the following year.
The name Cleistocactus comes from the Greek word 'cleistos' meaning closed, referring to the strange tubular flowers that emerge at right angles to the stem of the plant. In some species the flowers remain almost completely closed, on maturity the stamens and style just protrude from the end. In others, the petals at the end of the tube open quite wide. The other fascinating tendency is for the flower tubes to be bent, rather like the spout of a coffee pot. Sadly, the plants have to be well matured for flowering to occur, although I have had regular flowers on seed-grown plants of C.hildegardiae after 7 years. Another exceptional species is C.vulpis-cauda which is soft-spined and sprawling, but produces strongly curved flowers with a magnificently intense orange tube.
|Cleistocactus samaipatanus was grown from cuttings provided by the 'Exotic Collection' back in 1977, and has been regenerated a couple of times since. Pale green shoots up to half a metre long radiate from the base. In age the tips descend, although individual stems can be planted at an angle to make them stand up a bit more! Flowers can be expected after the stem reaches 25cms, and they are mostly carried at the end of the shoots. The brown, woolly knobs of the buds are slow to develop and sometimes they will become dormant and resume the next year. This immensely decorative species is easily propagated by cuttings - just take an arm off at the base carefully with a scalpel. Dormant buds will eventually develop when the plant has sufficient vigour!|
Cleistocactus includes a number of plants which have been described by authors as Borzicactus, Bolivicereus, Clistanthocereus, Hildewintera, Winterocereus etc. I don't share the necessity to describe every plant with different habits as a different genus, but I acknowledge that there are different tendencies in these groups. Grow the plants and see for yourself!