Cleistocactus strausii
The cactus prefers free draining soils, strong sunlight, but not high temperatures — in fact it can withstand hard frosts down to -10 °C. In its natural habitat it receives plenty of water during the summer, but almost none over the winter. In cultivation, watering too much in winter often leads to root rot.
Disocactus flagelliformis
Rattail cacti are very easy to grow, being suitable for a greenhouse and container, indoors or out. These plants need a minimum temperature of 6 °C (43 °F). They should be grown in bright, indirect light, in a fairly rich potting mix. The best compost consists of four parts sandy loam, and one part of equal quantities of sand and crushed brick. They should be repotted every other year because their soil tends to sour. This doesn't mean, however, that they'll need larger pots. Once the plants are established, keep the compost moist from April to October; less water is required from November until March, just enough to keep the stems from dying back. In the winter, old or discolored stems may be cut out at the base to encourage new growth.