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.
Cattleya rex
This species does not tolerate dryness for long periods, so watering must be done regularly and should be reduced in frequency during winter. However, the growing medium (cork slabs, baskets or pots) must have good drainage, so the roots can dry properly after watering or root rot may appear.