The soil is naturally sandy, not added with sand. it is very well drained but in this species high temperatures are important fo rit to grow to mautrity and flower every year. Coarse sand and a good commercial compost 2.1 would be fine. The plants are dormat prior to flowering, some three months. Sometimes they lose their foliage during dormancy, in ohter cases they just stop growing but keep the foliage. This you regulate by giving very little water then. They are often found in deep shaded conditions.