Habitat: South America (particularly Bolivia and the Andes)
Cultivation: The Cleistocactus require exposure in full sun and rather high temperatures that never fall below 6/8 ° C. Like all cacti, they are particularly sensitive to standing water, which you should avoid.
Curiosity: The name comes from the greek kleistòs, that means close, and it refers to this cactus flower corolla, which does not open completely.
The genus Cleistocactus is made up by cacti which mainly come from Bolivia and the Andes, they have a column stem with few branches (those present depart from the base of the plant), with long whitish thorns that, in most species, remind a dense whitish hair. The size can vary considerably, ranging from 20 cm height of Cleistocactus winteree to 2 meters of Cleistocactus strausii. It is, basically, very long-lived plant.
The flowers have bright colors like red or yellow. They bloom in spring and summer when the plant has reached maturity, that is, after a few years (about 7-8 years of age). They sprout in the upper part of the plant, they have tubular and narrow shape, and never open completely (from which the name of the plant). Because of this feature, the stamens come out of the half-closed flower corolla.
VARIETY AND TYPES
The genus Cleistocactus includes, according to the most common classifications, 49 species. We list below three of them which can give you an idea of the vastness of this kind:
- Cleistocactus crestatus
It’s the variety that grows with major ramifications, assuming an almost crested shape. Being perfectly compatible with all other cacti, it is often used as a rootstock.
- Cleistocactus strausii
It reaches two meters in height, with large flowers about 10 cm and red. It is particularly sensitive to vernalization, if it winters in apartment, it will hardly be able to bloom in the following spring.
- Cleistocactus winterii
It barely reaches 20 cm in height and it is particularly suitable for growing in pots. The thorns are not whitish as in most cleistocactus, but blond and very dense.
TIPS FOR GROWING
The Cleistocactus are sturdy plants with rapid growth and because of that some varieties are often used as a rootstock. These are our guidelines for proper cultivation.
- The Cleistocactus want an exposure in full sun, as generally required for cacti.
- The temperature must be rather high and must never drop below 10 ° C (6 ° for some more robust species).
- Water moderately in all seasons, taking care of standing water. In winter, watering must be suspended completely.
- For what concerns the soil it is recommended to choose one specific for cacti, well-drained, or a mixture of universal soil and sand in equal parts.
- To sustain growth, which is quite vigorous, it is advisable to fertilize once a month from April to September, using a fertilizer rich in phosphorus and low in nitrogen.
- The repotting may also be necessary every year given the growth of the plants. As with all cacti, please protect yourself with gloves during the operation.
The Cleistocactus reproduce either by seeds or by cuttings.
The sowing must be done by using fresh seeds and a jar filled with a specific seed mix for cacti. The seeds must only be put on the ground, not underground; the vessel must be placed in a warm place and bright but not under direct sunlight. Take care to keep the soil always humid, and you will see the plants sprout in a few months time.
The cuttings are taken from the stems from June to August, they may be buried in a soil rich in nutrients when the wound has dried.