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.
Pollination
Rain pollination is used by a small percentage of plants. Heavy rain discourages insect pollination and damages unprotected flowers, but can itself disperse pollen of suitably adapted plants, such as "Ranunculus flammula", "Narthecium ossifragum", and "Caltha palustris". In these plants, excess rain drains allowing the floating pollen to come in contact with the stigma. In rain pollination in orchids, the rain allows for the anther cap to be removed, allowing for the pollen to be exposed. After exposure, raindrops causes the pollen to be shot upward, when the stipe pulls them back, and then fall into the cavity of the stigma. Thus, for the orchid "Acampe rigida", this allows the plant to self-pollinate, which is useful when biotic pollinators in the environment have decreased.