Hi Boroma577. I wondered that to and have worked it out.
Wonder how they survive in the desert!!
It must be because of a substantially fast growing root system and the persistent presence of sub-surface moisture.
My comments were posted to basically stop people supposedly simulating their own perception of a desert in their backyards when trying to grow these tings. In other words I was trying to stop them from planting these seeds in pile of gravel and not watering them and then wondering why they failed. Mine get watered twice a day due to automatic watering system from rain water tanks and they love it. A lot of people give up on these plants for this very reason; they think they are too hard to grow. They are not really once you understand their needs
In past years the plants I have put into say 6” tubs and then sat them out in full sun on my concrete or pavers (because they must like it hot and dry) have all died before flowering account the heat. Same goes for hanging baskets. The roots get too hot and fry out.
I urge everyone to give them a go next spring. They are very stunning and most unusual in a suburban garden.
Cheers,
ALLAN